I'll play along. Much of my thoughts are based on many manufacturers stopping/slowing the megapixel race with a majority of the latest releases. As an example Canon's most recent "top end" P&S announcements have been 6mp cameras with a "decent" ISO 800 capability, with IS built-in.
My guess for DSLRs in the next 2-3 years. APS-C sized sensors will still rule for most manufacturers, except for Canon - who will still have a mix of 1.6x and FF, not sure if their 1.3x sensor will see it past the 3 year mark.
I see the likes of an Rebel XT/D50 camera with 6 to 8mp's at a $350 price point with a 18-55 intro lens. Better noise handling even at ISO 1600, and even better dynamic range.
As for cameras like the 30D and the D200, I see them in the 10-12mp range at a $500 price point for the body only. Again with better noise handling even at ISO 1600, and even better dynamic range.
At the $1000-1300 price point for body's alone I see APS-C sized sensor cameras with 12-16mp (with better noise handling even at ISO 1600, and even better dynamic range of course). F100 "pro build quality) with 6 to 8fps
In the $2000+ range it gets cloudy. For I don't see Nikon going full frame for at least 5 years, and that will be a different product line all together. A new lens mount with an adapter for AF-S lenses to be shot at lower resolutions, sort along of the lines at their HS crop on the D2X - the difference would be that the HS crop would automatically be selected by using the adapter. Otherwise for the new mount would require a menu selection.
In this price range I see Nikon going to 14 to 20mp. Think sort of an F5/F6 with APS-C. For Canon I see the replace to the 5D in 2-3 years being in the $200 range with 16mp. With the 1Ds replacement coming down to a $4000 price range with 20-22mp. Maybe by this timeframe Canon will offer digital specific wide angle lenses for the FF format.
In the $5000+ arena, I see MF digital being able to compete at the low end of this range with 22mp cameras, and moving up the scale with sensors that offer 40-60mp sensors.
I will need to see a reminder in iCal to bring this thread up in 2-3 years and see where things really have gone.