Are you talking custom crankshaft or just an offset grind?
I had a mate who was a bit of a wacko, and he wanted to the same thing!!!LOL!! Ok so lets be realistic, you can maybe get .75mm from the bore wall, you 'may' be able to offset grind 'a little', but lets face it, there is not alot of room in the case for a larger diam crank throw without 'alot' of die-grinder work and maybe some welding? The other thing is pistons. I have a contact over here that make pistons from scratch. Basically, he turns up to your shop with his van and his 'plastacine', does the math, takes your math away with a mould of the cylinder head, and comes back about 3 weeks later with a new set of pistons!! Last set I fitted were to a Nissan RB30Hybrid that ran a 12 sec pass and melted the electrodes off the spark plugs!!! Put the pistons were fine!!!! But they COST!!! What sort have things have you come up with?

Sixpack