Finally got around to play the rest of ClamSpammer's packs, and solved all but one (sent you the solutions via e-mail, unless I confused your address with BulletRide's).
"From the Brink" of Pack 04 somehow got me stumped, it looks like the bomber is the only way to get out of the starting boxes, the bashers used elsewhere as well, yet there are 4 blockers.
"The Floodgates Open" is a very unique puzzle without glitches, where you have to go through possible pathes and timing for the 6 worker lemmings to get them not interfere with each other. I think I abused a digger there digging down at the side of some terrain, as I got one digger left.
"Builders Cracks" was pretty tough.
I went right for the challenges in your latest pack, and some were pretty interesting, some others not as much. But I like the idea of having two difficulties for each level. It looks like you had both versions in mind right from the start, or did you design the challenges first and then simplified them for the regular levels?
For the Xmas08 pack, I think I backrouted the last one pretty badly.
btw, I agree, this one could be stickied again...