After blowing up a fair few Tamiyas, I moved to using 30A Powerpole (or compatible) connectors on Potholer's recommendation for all the Imperial College CC drills. They're hermaphroditic (neither male nor female), and you can do clever stuff by orientating them + supergluing them so you can't connect them incorrectly. The 'locking' is by the deflection of the actual pins that carry the current, so if they're physically secured they're connected.
Again, you'd have to bodge the panel mounting, but at least they're pretty much flush (no knobbly bits / clips).
I think the problem with the Tamiyas was that because it's a pin + sheath connector, as soon as a bit of grit gets in the way / messes up the tolerance you have a spark gap which at typical drill currents is a death sentence.
Here's a page with a cut-away photo of their design:
http://www.westmountainradio.com/content.php?page=supportrr
They're something like 60p per terminal, and you can find them often for sale in small quantities on eBay if you don't have a Farnell account.
