I saw something over on the BuildTak website that I thought was cool and wanted to eventually give that a try. In their version they include a thin/bendable steel sheet and the BuildTak goes on that; all that is then magnetically-attached to the print bed. I bought one of these magnetic project mats from iFixit, a variety of magnets, a second C2 bed and a spare BuildTak sheet. I then designed/printed some fins and here's what I have so far. I've used a clear version of a water-soluable Elmer's glue to fill in the bottom of the print bed to hold in all the magnets. Some of those are the rare-Earth types and some are just the cheap ones. The detailing at the back of the mat is to surround the plastic bar near the Z-rods and yet not collide with either X/Y stepper. I've repurposed some of the trimmed-off mat material (which includes a thick foam layer) in order to grab the bed from both sides with those bolt-mounted fins I printed this morning. The BuildTak sheet then goes on top. The magnets hold it firmly. The side fins prevent side-to-side movement since they're trapped with that foam layer. The back detail locks it in place so that it doesn't move back. The only freedom of movement would be to slide forward, which is the intent at the moment. And yet, the collection of magnets seems to be sufficient. The thought would be that even stubborn thin parts like coins could be removed just by bending the magnetic mat + BuildTak combo. The foam in the magnetic pad is rather firm, moreso than the average mousepad's. It's stiff enough to provide a flat surface, especially since it's magnetically held to the print bed now. Just waiting for the glue to dry to test this out.