… and we want all of the above at a $500.00 price point. 
There are a lot of good suggestions here. I keep thinking that some of the hardware requirements for the multiple stereo loops, long loop times, undo, and such would push the costs somewhere between the Stompbox and Eclipse classes.
The poor or nonexistent MIDI implementation turns me off from a lot of hardware loopers. I can understand a delay following a MIDI-locked device might get away with tap tempo or a millisecond equivalent, but a looper? Sync drift is OK, if that's what you're going for, but my rig is a tad too complicated for "almost rock-solid".
Har mentioned this above, and I'd like to add the usual stellar MIDI control over the various functions of the pedal. Nothing irritates me more than having to buy a proprietary switch / pedal component to get full use out of an effect device. Something like this SuperLooper is going to need a lot of footswitches, and external MIDI control is the "cheap" and logical way to implement it. Aux switch inputs don't hurt, but …
Har also mentioned the Eventide-class pitch-shifting and tempo stretching. I say to take this a step further, and you'd really have a unique entry into the field. Diatonic "smart" harmonizing locked to key and scale on the loops. QuadraVox on steroids. The PitchFactor already provides for some unique looping effects near 100% Feedback (or feedback under expression pedal control). The limitations are the single stereo "loop", the 2 second maximum delay, and a lack of many of the standard looper functions.
So, take a PitchFactor (or four Pitchfactors), add maybe 4X-8X the DSP processing, and 10X-15X the available RAM, sprinkle in some select looper functions, try to keep it under $2000.00, hope like hell that the economy turns around, and hope it takes NAMM by storm. 
