I know you said interchangeable lenses, but if you want a small one check out the Sony rx100. The sensor is 13.2mm by 8.58mm. Zeiss 1.8f lense. Shutter speed up to 1/2000. You will have $ leftover. Sony also makes a small interchangible camera as well, and they have been really playing one up to nikon and canon for the small market.