cheers guys :D
i was thinking Callahan vintage trem for the 6 string, then a hardtail 12 string neck on the other side. the necks will have Cocobolo fretboards with block inlays, and the headstock faces + guitar body will be painted with black nitrocellulose.
Warmoth do a doubleneck strat body which is where I got the idea, but I don't like how it loses symmetry:

so I made my own template by tracing round a Strat template twice in 2 locations a fixed width apart on some MDF, then drawing in the corrections to make it one doubleneck body. the body is actually pretty light considering its 18" wide, and is probably no more heavier than a lot of single mahogany strat style bodies out there...