Maybe I'm fooling myself, but with some judicious bending of the metal strip and the angle of the tab vs. the strip the Griffin TechSafe seems to fit in my MBP15R fine and I am able to close the lid, just barely.Of course I couldn't walk around with it that way, but that's the whole point of securing something. I also added some thin film label plastic to the tab, hoping to reduce the risk of causing a scratch where it rubs.
Not a perfect solution, and its nothing that couldn't be cut through with some tinsnips, but for a person like me who prefers to avoid cases that even slightly reduce heat convection cooling that the MBP depends on, it seems to do the trick for me until someone comes up with something better.