I haven't read the whole thread but here are my 2 cents. I am in the same park as you, using a liter bike as my do it all bike. Commute, track & very rarely get some groceries for the heck of it
Without a doubt I can recommend the GSXR 1000. Of all the liter superbikes, I believe these are the most "streetable" for the lack of a better word.
Get any 03 - 04 or 05 - 06 models & do 3 things to it.
- Spiegler handlebar conversion kit
- Vortex rearsets that can be had cheap from any race forums or Ebay
- Taller windscreen
After you have all the above, adjust your rider triangle to preference & ride. These things have massive torque, rarely need any maintenance & give good mpg if you are smooth with the throttle. I have owned an 06 & now I own an 09. For my purposes, i really miss the 06. Excellent stock ergonomics, excellent power band, very intuitive handling & really good mpg. The 09 is a great bike too, but the small fuel tank, poor mpg & comparatively uncomfortable ergos are points against it. Of course at the track, things change. The 09 feels a lot better, brakes better & turns better.
Good Luck with your quest.