I always thought that is one of the many jobs for the bun. Soak up (or as we say in the south) sop up the juice. In New orleans we rate our po-boys by # of napkins. A great roast beef po-boy should be a 4 napper. If it doesn't threaten your elbows the burger is over cooked. Just Sayin.
That's the way it's been with me as well. The bun does the job of this burger lift on its own. That's even more so if it's toasted.
Cute little idea, but it's a bit gimmicky for me. Besides, I have more than enough gadgets to play with this year already.
Here's this year's favorite - I've been supporting this company since they started selling their gear in Canada and I've got everything but their upcoming (and totally secret and unannounced) BaseCamp stove:http://www.biolitestove.com/
In fact, this or next weekend I plan to try out a few things on the BioLite grill. Keep in mind that this is a wood-fired stove that gasefies the wood for better combustion (like a rocket stove), so the results ought to be more variable than a gasser or charcoal grill.