Finding a good interface at 2K should not be a problem. At that price point, not only should the on board pre's be really good, you should be able to get motorized faders. I wouldn't worry too much about the MIDI though as many keyboards have switched to USB and there are a few MIDI/USB adapters out there that work well.
If you are going to throw that kind of artillery at the computer, really recommend getting a high end rig. i7 chip or one of AMDs 6 Core chips. 6-16 Gig, 7200-10K or SDD drive. What you are proposing is getting at the high end.
Here is a suggestion, you might want to start out smaller (not sure the objective). Get an 8 channel AI (Tascam 1800 seems to get good
reviews, but something at that level) for about $300 (GC). Get your mic collection and studio set up, get going, then if you want to move into a higher level the only area you will have to replace is the AI. I think 8 channels is a really good start and can record almost anything except a whole band with drums. Even that can be accommodated by simple using a MIDI drum track for base tracking, record everyone else, then lay the real drums in later, or some combination of that.
Hope I helped and not confused.