hmm, you are really describing the Fuji X-100, but pockatable it is not . . .
already, the S95 is twice as bulky as my P&S and it barely fits in my pocket.
The NEX is about as small as any APS-C can get and it definitely does not fit in my pocket. The X1 is not small either, and cost a little more than $500, last time I checked.
My P&S (1/2.3") has an f2.8, the S95 (1/1.7") has f2.0 and the NEX (APS-C) has f2.8 (16mm). They are all equiped with IS and high Mp count (10-14Mp). ISO-wise, I'd say that they are useable to: P&S up to 200, S95 up to 800, and NEX up to 3200. Sure, I would like a P&S (even a cell phone -
Nokia's N8 has a 1/1.7" sensor ) that performs at 3200 . . . with zoom
We are all happy that the S90/S95 even exist - if you remember, only a few years ago, almost all P&S had a 1/1.7" sensor. The race for compact zoom and superzoom, coupled with noise reduction and IS, enabled the 1/2.3" sensor size to become more popular, with loss of IQ at higher ISO, but so much cheaper to manufacture.
You are asking for a lot - take a closer look at the Fuji-X100. It is as close as you can get to your spec, and it does NOT fit in your pocket. Heck, none of the MFT fits in your pocket either. And none meet your price point either . . .
I do not think that Canon want to upgrade the S90/S95 (evolve maybe, no major spec changes) - they already have the G11/G12 (same sensor). A mirror-less APS-C system would become very similar to the Sony/Fuji approaches, physics are physics. An MFT approach would have some minor size benefits, but then the 'not an APS-C' comment would be heard al-over.
If Canon plans to upgrade the S95 they should consider an APS-C size sensor. Leica did it with the X1. Keep the same F2.0 zoom with macro, upgrade to 1080P video and 12MP. Most people still want a pocketable camera. The Sony NEX cameras are not pocketable especially with the 18-55 zoom. With the pancake lens-maybe. Add some weatherproofing to the S96 camera and you would have the ideal travel camera for most people. I think most people would buy it if it sold for around $500. Let us hope that Canon makes this camera.