I'm hoping that's not the case but before we can jump to any conclusions about meshes and bhavs and such we need to figure out how to get them out of these damn .arc files. I'd be lying if I said I'd tried very hard to do that though. All I can say is that they are NOT this.

Edit: to fix my forum code fail. Again.

So I was lurking here the other day, looking at the stuff ripped from Life Stories, and it occurred to me that maybe the same could be done for the various console versions of the game. I remember playing one of them a pretty long time ago and it had some pretty cool objects and, although a quick google image search reminded me that the console version's graphics suck ass, i figured some of the objects might still be cool to have in the real game (like the trampoline, or the crazy futuristic floating water hot tub thing). So I arred a copy of the Sims 2 for the Xbox (figured it's chances of compatibility would be better than that of the PS2 or GameCube versions due to the PC-ishness of the Xbox and it's file types) and extracted the files. Given that I know next to nothing about the Sims 2 modding I'll list the files here and those more awesome than me can tell me which ones might be of use.

root\default.NGH
root\default.xbe - This is an Xbox executable file, like an exe (some documentation here.)
root\sims2.bin
root\DATA\ambients.arc - can't say I've found any useful information about .arc files
root\DATA\animatio.arc
root\DATA\audiostr.arc
root\DATA\binaries.arc
root\DATA\characte.arc
root\DATA\datasets.arc
root\DATA\edithtre.arc
root\DATA\effectsa.arc
root\DATA\effectse.arc
root\DATA\effectss.arc
root\DATA\emitters.arc
root\DATA\flashes.arc
root\DATA\fonts.arc
root\DATA\levels.arc
root\DATA\models.arc
root\DATA\movies.arc
root\DATA\quickdat.arc
root\DATA\samples.arc
root\DATA\shaders.arc
root\DATA\soundeve.arc
root\DATA\soundtra.arc
root\DATA\textures.arc
root\DATA\index1.ind
root\DATA\index.ind
root\DATA\audiostr.xsb
root\DATA\audiostr.xwb
root\movies - Just a bunch of .xmv movie files, like the EA logo and some cutscenes.

If you want one of the files just say so and i'll upload it. or if you want to try a different version (PS2 or GameCube) and/or game (The Sims, The Sims: Bustin' Out, The Urbz, The Sims 2: Pets*, The Sims 2: Castaway**) i can arr it and extract it's files. Also, no requests for MySims because that would be stupid (and it's been announced that it's coming out for the PC anyway).

*unlike previous games, pets is also available for the Wii, but not the Xbox
**same as pets but no GameCube version

Edit: to fix my forum code fail

Edit 2: Linking files.