Take a look at the Nikon D40 or D60, those are pretty small DSLRs (I am sure there is a Canon equivalent as well). I have travelled with a DSLR and found that it is not that big an issue (especially if you have a case that fits in a backpack or so)...it is when you start collecting lenses, that travelling becomes an issue
If that is still too big, take a look at the Canon G10.
Hope that helps