I don't think any sound cards (except for maybe very high-end, hard to find ones) have hardware/software ability to mix tracks. You might want to try CoolEdit with the Studio plugin. It'll give you 4 tracks, I think. You can mix them seperately. Or of course, you could spend $30k on Pro Tools
Anyhow, you'd be very hard pressed to find a sound card that accepts 8 mono/4 stero inputs, which is what you seem to be looking for. You might have to record it seperately.
Or, Yamaha and Korg (I think it's those two), have some new stuff out that's a 8 or 12 channel sound board with effects, compressors, gates, etc. built in, and it allows you to master to CD without a computer. I'm sure it has some sort of computer interface, as well. I'll see if I can dig up some links.
Apple? Macintosh? What are these strange words you speak?