Check out the Olympus E-420 with the Zuiko 25mm f2.8 pancake lens. Hailed as the lightest and smallest DSLR, it makes a nice light and compact package with the pancake lens. Sweet huh? This should give the Canon 450D and Nikon D60 some competition.
Incidentally, Nikon makes a 45mm f2.8 manual focus pancake lens if you want to try this out on a Nikon DSLR.