Hmm, nice idea, stops dust.
Hmm, bad idea,
what sensor size? Probably be small, hence low DOF
what quality optics. People slate sometimes EF-S as being the 'cheap' option. If the sensor is small, then you only need good optics for a small area. What is the QC going to be like?
How much? Each time you buy a lens, you are basically buying the important part of the body again.
Only two lenses? Seems to be a little low for starting a system and getting a foothold.
Might as well have two compacts in your pocket.