Yes, JLH (Jonathon's his user name here) for one converts them, since the Maestro is front wheel drive and the Minor rear. Dunno the full details, but it invilves a new crank and some block machining for things like oil seals.
Crank is only modified for the spigot bush, and does not require replacement. You will need a dedicated flywheel and some mods to the alloy breather plate along with a modified 1098 backplate.
I bought one really cheaply - in excellent 'almost new' condition - found it was possible but not easy, and so sold it on to a Maestro owner. Kept the unleaded head (also 'new') - and sold it on for a nice 'earner'!