I dunno, They seem really out of place if you ask me. Personally, I think they would look best without a logo at all. If thats not an option, Then why not make one that either snaps into place through the grill holes and is moveable, Or is magnetic that will either stick to the grill or to a removable peice that goes in behind the grill sandwiching it between the magnetic front of back peice and the logo which could be magnetic or metal..
Or the logo could be like a pin, where it has two little pegs that go through holes in the grill, and clip into a back peice. I like the logo on the front of my 80's but, I think anything that can be done to not call attention to these speakers is the way to go.