I really wouldn't do too much to your Melody Maker, I mean, it sounds a beast and probably plays well, so isn't that enough? If it holds tune alright, no need for locking tuners. The one thing I'd consider'd be a Bigsby, but they're bleedin' expensive, and you need to get rolling saddles for your bridge, as well as a decent nut, and locking tuners...
Personally, mate, I'd just go with a £1.50 plectrum holder to stick to the back of the headstock. Sacralige, maybe, but very functional. I have one inside the soundhole of my Gretsch.
