Several larger pools are running 0.8 or almost-0.8. Largely stock software (with maybe a patch to filter out SatoshiDICE transactions here and there).
Hmmm, not really the answer to my question. When a block is found, don't you have to download the whole block to see which transactions they included so that you can build the merkle tree?
The removal of redundancy that Jutarul mentioned, is that how 0.8 works?