After a little bit of reading, it would seem that I'm fine on the sub (or as fine as I am now, without the ground tab screwed in) with the little extension cord. However, it would seem that my second idea (the independent ground wire) is just asking for trouble. It might work, but it might kill me or my family, too--I simply do not know, and a little inconvenience is vastly preferable.

I am the Doctor, and THIS... is my SPOON!