IVA reverse gear requirement

I've long held a derire to build an R1 powered Fury but have put my car building plans on hold for a few year due to a growing family.  My head has been turned by the forthcoming Sylva Spectre though so I can't see me holding out too much longer.

Perhaps any R1ot owners out there could give me some idea of how to solve the lack of a reverse on a bike engine installation.  My understanding of the mecanicals in the R1ot and Spectre are that a shortened chain drives the Fiesta diff straight off the drive sprocket on the engine, which doesn't appear to leave much scope for a mechanical reverse without going for an expensive specialised diff.  Is electric an option?  If so how does it go about driving the wheels?

Thanks in advance,

Al.