The equipment should consist of:
1 damage dealer crossbow - Scoped (anatomically-aware) Super Zephyr Crossbow. Tornado is stronger but has fewer, weaker criticals, a 2% CtH penalty and also important - 15% instead of 10% move and shoot penalty. Ideally you'll be shooting first and then moving but now and then you won't be able to do so because sometimes you'll have to hide behind a corner to lure the enemy in your trap, and when he steps on it he'll be rooted and you likely won't see him unless you step out from cover again. Also on some rare occasion a bug happens where the enemies can fire at you but you can't fire back unless you move. This problem is not special to crossbows and can happen with any ranged weapon.
1 special bolt spammer crossbow - Scoped (anatomically-aware) Pneumatic Cyclone Crossbow. I'll get more to it later.
Armor and boots both made of infused syphoner leather which provides good heat and acid defenses but also lots of dodge and evasion bonus - as a glass cannon you'll need lots of it. Utility belt which gives you 2 additional utility slots so you'll have 4 (5 with Quick Pockets). You'll fill all those slots with special bolts. Smart night vision goggles to boost your special attacks and actually hit under low light conditions. You can use a shield to your own liking. I prefer a low frequency efficient shield emitter for most of the time.
I'll break down some of the not so obvious feat choices:
Snipe - Usually it's seen as a sniper feat and many people (including the popular youtube guide maker Nerd Commando) like to skip it but I cosider it as essential for crossbows as well. While snipers are way stronger by base damage alone (plus they can be made with smart modules) crossbows have one significant advantage - they are completely silent weapons. In your first round you have a good chance to silently kill small groups of 2-3 enemies without alerting anybody else on the map, so with more quick encounters you'll use Snipe more often than with a sniper.
Blitz - Crossbows are slow weapons and as with any other build it's essential to plan ahead on how you will make most out of your AP. Your first combat round is pretty clear. You'll use Special Tactics ability for the extra attack and open the combat with Snipe, Aimed Shot and Kneecap Shot - all from your damage dealer crossbow. From the second round on you'd normally be left with 2 shots per round. This is where your quick Cyclone crossbow comes in play. Made with the pneumatic reloader it fires for 17 AP per shot so together with Blitz and adrenaline shot drug you'll have 90 AP for that round which allows you to fit in 5 (!) shots with the Cyclone (17 x 5 = 85). With the effect of adrenaline shot alone you'll still be able to fire 4 times with it (68 AP) and even when fatigue kicks in you can still shoot twice for 34 AP out of 35 available. As a side note - In tight areas I like to bottleneck enemies and block them of with traps while dealing with fatigue. Often it will buy you enough time till it wears off.
Quick Pockets - No longer neccessary since patch 1.0.1.4 as the special bolt stack limit was greatly improved (It used to be only 5). I replaced the feat with Concussive Shots. This also opens up the trappers belt as a viable alternative now if you find yourself doing well with one less stack of special bolts. (thanks epeli)
Pack Rathound - As a crossbow user there is no reason to raise STR above 3 but you'll depend on traps alot and unfortunately they also weigh alot just as the bolts, batteries etc if you carry many. I don't mind a bit of inventory management so I can live without it until level 20 but don't go down to DC without it. Even if you disregard loot completely you won't be able to prepare properly. If you're having financial problems you might want to take it a few levels earlier.
Kneecap Shot - While it's pretty mediocre for pistols and SMGs it's amazing for crossbows as you can afford to have high perception which gives you better damage. It count's as a special attack and is therefore affected by smart goggles bonus. With high perception you have a pretty good hitchance and crossbows have a better range than most weapons, meaning you can attack from afar but the average enemy affected by Keecap Shot will have to spend most, if not all his AP to close in - very good to kite away when fatiqued. It's also the best attack against melee opponents as you don't wont to have those point blank in your face because then will suffer either move and shoot or close quarter penalty attacking them.
If you're worried about survival and want to focus more on defense, at level 12 you can raise INT from 6 to 7 instead of PER and replace Quick Pockets and Kneecap shot with Power Management and Skinner, but even as a permadeath (ironman) guy I prefer the more offensive approach I posted above.
Feats I see here mentioned I would not recommend:
Ambush - While it's pretty good it's too situational to be reliable and requires some experience. Which tile counts as illuminated and dark is not always as obvious but if you tend to have lots of incendiary bolts you can consider taking it late game for DC instead of Kneecap Shot. Remember however that with heavy trap usage and Deadly Snares you'll hit critically anway so it reduces the usefulness of this feat. It's better for snipers. Same reasoning applies to Recklessness.
Trap Expert - With high enough traps skill there are not many enemies that will detect your traps so It's mostly a waste to pick this in a feat starving build like this.
Nimble - I use it for most dodge/evasion builds but there is simply no room for it. With syphoner leather armor you only get 5% armor penalty so your Snipe and dodge/evasion won't suffer much. Sure, you also lose the bonus to them but it's not good enough here. Besides, 10 agi + 1 from food I recommend as your supplement is plenty. If you want it consider Skinner first.
Distribution of skill points:
Always max out crossbows, dodge, evasion and stealth. Raise traps so far that you can not only detect but also recover traps for yourself (you need 20 points above the trap disarming difficulty).
Crafting is obviously mandatory, not only for the crossbows, armor, etc but also for the traps and special bolts. Thanks to 6 INT, junkyard surprise and 15% crafting bonus from the Core City basement bonus you don't need to max out crafting skills, not even close. I found it there is even room to raise enough chemistry (60 effective skill) to craft Mk III incendiary bolts which are amazing in tight spaces. Too good to be left out. Chemistry should be your last priority however. You'll also need some biology for bear traps and thanks to the crafting bonuses I mentioned above putting 39 points in biology is enough to translate it to 65. For chemistry it's 38 points (equals 60 effective with bonuses).
With all this there is enough room to raise both lockpicking and hacking to effective skill of 100 and that's a very solid value.
