I think the open source model building might just work on freespacemods- the site has the ability to create categories/sections/etc, to upload lots of models, and there is a comments section and screenshot available for each mod.
If each model got it's own category until finished (such as "GTF Whatever"; similar to the "Fighters", "Bombers", "Small combat vessels", etc), with each newer version being uploaded to said category, this stuff will work. When the model gets finished it could get moved to the proper downloads section, and the incomplete version could be either archived or deleted- along with it's developing category.
Let's see Swantz's opinion about this though.