As a thought, I remember ages ago looking for lspci for OSX too.
Finally found one, and it worked well. I think it was by some of the guys that work on the Hackintosh side of things, so if you look through the various Hackintosh sites for lspci you should find it.
If you don't, let me know and I'll see if I can dig it up. It's been a while though.
Note - it did work well (perfectly), so definitely recommended.