I hate to bring them up (again) because I'm afraid that I'll be accused of being a GMA shill...but I'm so excited about my Green Mountain Audio Callistos that I can't help myself. Of course, I choose to buy my Callistos (new) 3 months before Roy released his new line (which he claims even the Eos I bests the Callisto - I'll have to hear it to believe it). All 3 iterations fall below the $5k threshhold:
Eos I, $1,995 pair
Eos II, $3,200 pair
Eos III, $4,500 pair
GMA's been around for 20 years, so they don't really qualify as a "start up", but GMA does seem to fly beneath the radar, and may be one of the best kept secrets in audio.