Banjo Tooie has now been hacked to work with the Everdrive 64! This means that the Everdrive 64 now works with every commercial N64 game, and every N64 program except for the unofficial Super Mario 64 new level hacks (which is down to the hacks themselves not running on real N64s, not the Everdrive 64). Unfortunately the Banjo Tooie fix is only for the NTSC version of the game, so if you have a PAL N64 then your TV has to support NTSC mode (almost all new or fairly new TVs do, at least in England). Thankfully mine does, and I can confirm that the hack works and BT now starts and plays fine on my PAL system.
To get BT working on your Everdrive 64, go tohttp://www.assemblergames.com/forums/showthread.php?43143-Banjo-Tooie-(U)-NTSC-Crack-amp-Save-Fix-released-today
and follow the instructions in post #9, that's all there is to it!
Many thanks to Jovis, Dextrose and everyone else involved, and of course KRIKzz for making the Everdrive 64 in the first place.