im getting sick of them being called concept artists, a concept artist is some1 who designs something, a character, a building a landscape for a film, etc etc, Concept means the orignal idea, to develop and expand from. What you are looking for is a Reference artist, somebody to draw a character/watever so it can be used as a reference to create something, they dont have to make the visual design, they just have to demonstrate its features.
I doubt there are any REF artists here, I would have, but after consideration, ive found it isnt a good job, you spend maybe 1-3 hours drawing sumthing, then when the model is being made, the modeler blames all the flaws on the ref. At the moment, Im constantly being asked if i'll do refs, and it really does piss me off, cuz it means i have to sit at the computer, drawing for ages with no purpose or enjoyment for me, and then i dont even know weather they make a good model, or if i get the proper credit. I will only do refs for modelers I trust, because I dont like people making crap models using my refs, cuz all their excuse is "i followed the ref" sorry but that aint the case, 1 person can use a ref and get a completely different result to another person, as i've seen with my kakashi ref.
Anyway, thats my rant, i doubt u'll find any ref artists here.... maybe denza can help you out though....