The "pro" compacts such as Canon S95, Canon G12, Panasonic LX5, etc have decent low shutter lag compared to typical compacts. It really isn't significantly more than Micro Four Thirds which you mentioned, and with some pre-focusing can be virtually instantaneous. Try out a Canon S95 in a store to see.
The burst rate of these are pretty good too and will compare favourably with Micro 4/3 too.
The Olympus XZ-1 can do 7 or 15 fps in burst mode albeit at a smaller frame size than normal.
In my experience Micro 4/3 is not that expensive when you compare it to a similar setup from Nikon or Canon. Nikon and Canon entry level kits are nice and cheap beating m4/3 but the DSLR price benefit goes IMHO away once you move on from the kit lens in both.