I am thinking of a specific armor actually; http://fallout.wikia.com/wiki/Riot_gearI am assuming that one would probably need the GECK for it to work, but man that was always my favorite armor in the Fallout games

Second follow up question what about introducing the old West style weapons from New Vegas?

You basically have to find someone who can build the armor from scratch, and have them build it from scratch. How hard is that? I guess that depends on how good they are at 3d modeling. For someone who is really good at 3d modeling it would be real easy, maybe a day or two... for someone who hasn't used this kind of software before and only has Blender, it could take ages to complete...

So there is no clear answer to your question, it is all a matter of skill.

Right now we are still waiting for the Nifskope stuff to be sorted out, so I won't be making anything until I know those tools are stable.

What TeamBacon didn't explain is that Bethesda doesn't allow resources from their games or any other game to be used in mods. Hence the reason why someone would have to recreate the items from scratch.