Here's the latest engine swap in DSLRs: The entry-level 6MP Nikon D40 got a 10MP image sensor to become the D40x, putting it in the race with such cost-cutter ten-shooters as the Canon EOS Digital Rebel XTi and Sony Alpha 100.
The D40x ($799, estimated street with 18-55mm f/3.5-5.6 AF-S DX Nikkor; $729, body only) does not use the 10MP sensor of its upscale sibling, the D80, but, says Nikon, a "similar" APS-C-sized CCD. Figuring this was a lower-cost CCD, we worried it would show compromises in performance. Wrong. Image Quality data from the Pop Photo Lab proved about on par with the D80, the top camera in our 10MP DSLR shootout (February 2007). To wit: Excellent resolution through ISO 3200, stellar noise control (Extremely Low through ISO 400, Very Low through ISO 1600), Excellent color accuracy. Read the whole test here