To be honest, we could implement a very basic version quite quickly. For a small number of objects, we'd need :
1) Death animations for female
2) Some way of sorting out this animation timing problem (the enemy dies before you punch/shoot)
3) If I understand it correctly, death animations for armours would need "slicing up" in the same way
4) Tidying up the basic models / textures a bit
5) A couple of hair models
6) Linking existing armours and weapons to the 3d models
7) A few base textures / hairs / beards to choose from at game start
8) Tweaking the rigs on some models to remove clashes/glitches
9) Something else I've forgotten
If those were done, we'd be able to replicate what we already have in game, in 3D at a fairly crude level, i.e. basic male and female with existing sets of armour and weapons. The animation timing thing is a problem which we don't know how to solve yet, the death animations are in progress by Karpov now and the rest of the list is all stuff which is quite straightforward (and anyone could do with a little instruction), though in some cases time consuming.
For the more polished version, we'd need quite a while longer to get it to "look right" (adjust lighting, effects etc) and to rig and resize all additional content, make inventory/floor sprites and to implement the additional armours as things which have stats and appear in shops etc. There'd also need to be some in-game scripts written to change base clothing - i.e. a clothes shop similar to the existing barber shop.