Not sure which topic to stick this one under, but it's not N Gauge specific, so here in general will probably do :)
Just in case anyone wants to try and kit bash or otherwise scratch build (hmm, maybe there's a suggestion of which topic it should have gone in there? :) ) something *really* different. I remembered coming across this site http://douglas-self.com/MUSEUM/LOCOLOCO/locoloco.htm (http://douglas-self.com/MUSEUM/LOCOLOCO/locoloco.htm) a year or so ago. Lots of strange and wonderfully unusual engines :)
This one... http://douglas-self.com/MUSEUM/LOCOLOCO/patiala/patiala.htm ...the Patiala State Monorail was modelled in N gauge by the late Bill Avery - he of Port of Enn fame. It was an operational model, and looked really effective.
I'd like to see somebody (although probably not me) build the "Super Garratt" http://douglas-self.com/MUSEUM/LOCOLOCO/quadruplex/quadrapl.htm (http://douglas-self.com/MUSEUM/LOCOLOCO/quadruplex/quadrapl.htm) Although I'd also hate to think what the minimum radius would be (I'm not sure how flexible Mallet type locos actually are) I'm not quite sure what you'd need all the power for either. [Pulling the moon out of orbit?]