I know that this game's been out forever but I'm just now getting in to the modding aspect of it. Partly because I stumbled across
Toffisama's Princess of the Ring h-fighting game(which was made using 3D Custom Girl's models+mods) while looking for patches for the newly released Real Kanojo and partly because after checking out how much the mod community's advanced I can't help but want to dive into it again.
I really like this game. Almost enough to add a 3D Eroge section to Carrerachan for posting screenshots from 3D Custom Girl, Yusha, Artificial Girl 3 and the like. On its own its decent as an ero-simulator and a lot more easier to pick up and play than Artifical Girl 3 since you choose simple things like outfits and not complicated things the circumference of her vagina at 90 miles per hour when applied to a tsundere personality type(Not entirely knocking AG3 here. I love the game, but hate how much options you have set before you even get to play.)
But if there's one thing I hate about 3D Custom Girl it's how cumbersome applying mods is.
At the moment there's several mod packs being torrented, but because the instructions and names of each mod are in Japanese you often have to add mods one at a time just to make sure they're working correctly. Some people have reported crashes or games not starting after dumping 100s of mods at a time into their folder, though I think those cases are caused by people not having Japanese language support enabled. I know the times I've tried that I've never had any troubles running. It's the idea of having a big bloated mod folder and thousands of ones I don't want that still have me applying them one at a time.
So anyways, these past few days I've been wading through gigabytes of mods and kanji at
3D Custom.net in hopes of some day being able to have options to make girls like in some of the screenshots attached.
With a lot of the mods that are out(more backgrounds, items, body types, and the poser) 3D Custom Girl's really moved a long way from being just another click-and-fuck simulator to a full blown 3D anime character creator and through its license agreement which allows user created works to be used commercially you could very well use this to make a doujin game were you inclined, much like what Toffi has done.