So Dwayne, why don't just run the RCPRO Club 40 rules with the only change being .46 engines. I know a lot of guys that would be very competitive running a .40 against a .46.
I understand with the economy down folks are working at minimizing there hobby expenditure. Anyway you need to do what works for your group. Those that run a PRO .46 can take it out and bolt in a PRO .40 in its place and run a regular Club 40 event. No big deal.
I hope you take pictures and post the results of your race.