Ive seen welding guns in two locations now (wont say where as to not spoil) but they cant be taken and they wont do anything?

NO many people have wondered the same thing at least i haven't found anything they do?

Probably a feature that was abandoned mid-stream.

Off the cuff, maybe there was going to be some different type of weapon customization (besides upgrading with parts)?

yeah some characters holsters the weapon like this [/] (imageine [] is your back) and some other ppl hold them like this [\] there are animations for how you take out the weapon for each of the 2 cases.

the / form the weapon cannon is at the bottom and the \ form the weapon cannon is at the top.

DLC? People often claim that DLC features are built before the game is released and then held back to sell later... Perhaps we'll see the welding guns utilized that way.

Then right there is your answer to "What do they do?"- they lie around like untouchable clutter.

Something the developers gave up on halfway through their programming to meet a deadline.

What I want to know is why can't you use the paint guns? OR CAN YOU?!!!!

Paint guns used to be required to build Dart Guns in FO3. Too bad Obsidian knew they were one of the best weapons in the game and got rid of them in FONV because they could even cripple Deathclaw legs in one hit.

aye this poster makes a valid point.
i can see a sequel to the "pitt" from fallout new vegas in some form.
btw that was epic story.

I've noticed certain shovels in the game that act in a similar fashin - that is, when you land your cursor on it, it says "shovel", with no option to use it or pick it up. These shovels look different from the shovel you can use as a weapon.