Wait, sorry, I just noticed this- I don't mean to seem like I'm bagging on you- I'm just curious. How do you plan to use magnets for this? It'll be a royal b**ch to take a fully sealed, flush-mounted cover off that's held on by magnets unless the magnets are so weak that you can shake the cover off. Are you going to glue magnets to the cover and the sides of the cavity? Do you have a plan to facilitate removal? Also, for what it's worth, I'm a hobbyist who has never built his own bass, so my comments relative to someone like Wilser, Musiclogic, FBB, Msherman, and the other real luthiers who post here shouldn't mean much. I have, however, just done about everything known to man to modify my instruments from changing number of strings, retopping/refretboarding, reprofiling necks (width and thickness), adding 2nd control cavities, loads of electronic work, and all that. But, really, I am by no means a luthier, so take my comments as you may!