I tried a bunch of levels, and finally settled on Peggle Institute, level 7 using Bjorn the unicorn. When you start, try to slide inside one of the two circles at the top right and top left, and then fall thru and slide along the bottom arc. this should get rid of the bulk of the peggles. If I hit one of the greens I used it to line up shots that would take out one, hard to hit peggle and bounce right into the bucket thing at the bottom.
Took me three goes.
UPDATE: Big thanks to MAKA91 for doing a video (see below) - much appreciated, mate.