Bam! I joined both guitars on screen, played in photoshop, and came up with the double doom concept design..

..and where I am up to at the moment with it:
the headstock taking shape

routing the body - damn straight i'm going semi-hollow on this, it would be pretty heavy other wise

the diamond plate cut for the pickguard

Body is (again) Tassie Oak, fingerboards of massanuba, string through (except for the bass), one piece body/neck(s) and stylised headstock instead of them being separate, electrics will be EMG 81/85 in the tele side, and I've got a lace sensor fender jazz pickup and a set of split single coil precision bass pickups for the bass side. There will be a gibbo style 3 way in the top horn switching between the tele being on, both on, or bass on, 2 -3 way switches for the pickup selections for both sides, and 2 volumes/2 tones to control whatever pickups from either side when selected. I'm going to do the 18v mod for the EMG's as well. No additional thrown in quirks (yet), though I am contemplating a fuzz something in this somehow, would be cool to throw in a electro harmonix, we'll see how it goes.
Again, i'll keep you posted here if you like, or follow my site for the details.
btw - i got some inspiration from this - http://www.youtube.com/watch?v=xFYzW4axzjA