What is the limit to digital photography?

My Nikon D50 and its 6 Megapixel chip is now old news, even the lowly D40x has a 10 megapixel chip. So what is the limit for digital photography? Will we need to go back to using 35mm film lenses on bigger chips to get higher resolution any time soon?

According to Wikipedia the DX film sensor is 23.7x15.7mm. The wavelength of red light is 700nm. Assuming that the wavelength of light turns out to be the limit for cell size we have an upper limit of 33,800 by 22,400 pixels or 760 Megapixels.

That allows for a 9'x6' print at 300 dpi or a 28"x19" high resolution 1200 dpi print.

While physics may well make it imposible to achieve the limit itself, electronics and smart interpolation will probably make up the difference.

A 760 Megapixel camera would be more than a match for the 8x10" film of large format cameras. The Nikon D200 is generally reconed to match if not surpass 35 mm film. Doing the math this means that the 760 Megapixel camera would be equivalent to 13x8".

Update: Mrs dotFuture tells me that the limit is two wavelengths. Apparently the proof has something to do with Fourier transforms. Which puts the resolution limit at about 190 Megapixels.