No, that trick's the only thing I've got. The only conceivable way to win from that point is to send a climber up, and dig down one side of the thin piece. The left is obviously a bad idea - you need heaps of floaters if you want to have enough time for that one (unless some REALLY good grouping can be done somehow with the release rate?), and the right requires you to do it at 19 floaters, meaning you need 21 altogether - I'm guessing that's probably what he did. The best I acheived with any lower amount of floaters was 78% with 19 floaters total.
If you try building out of the starting place, you only need 5 floaters, but even if you climb and dig until you're low enough to make the thin part only one pixel thick, you can't build high enough with 3 builders, and no matter what you do you'll need at least one - not to mention that there's not much you can do at this point. A direct drop requires two builders, leaving only two to both create a landing space and get the crowd to the direct drop. Not possible.
The ONLY thing I can think of that I haven't tried that might work, is coming up with some builder setup in the gap to make the basher go through all the way, but since you'd need one to get to the exit and at least one to create a landing space (without worrying about how you're going to turn your climber around, since that's the only possible place for a landing on this one - use an earlier floater to do the bashing), I have no idea how you'd set that up with only two builders and only one lemming available to set it up. If you could somehow get a second lemming over there, without a continous crowd incoming, it could be done...
I tried a few setups with two lemmings at the top (not that one though, there wouldn't be enough builders since you need two at the start), by sliding one up and making the other a climber. The builder used to initiate the slide also was high enough that, if built after turning around, it provided a safe landing place, so one of them wasn't a waste at least. I couldn't really go anywhere with it though, not enough builders.
If you could somehow group together the lemmings well enough, could you possibly slide twice with 3 builders and without the digger? I doubt it, but if you could, you could slide one up while building the landing, make him dig at the edge then build across the gap, so that neither fall is fatal, then you just slide the rest of the lemmings up. The one that's trapped, that's what the climber's for. I have no idea how such a setup could possibly be made though.
