First up, I admire the drive to make games and start a company.
I think it’ll be hard to get investment or publisher interest without a proven team behind your game. That is unless you have a hot demo or prototype- say made by you, your brother and anyone else you can rope in.
Given that it’s a while away before you start the company I reckon you should crack on with any ideas you have now…prototype it, get a cheap engine (Torque)…see if its sound and if its fun.
Aim as broad as you can, alot of start-ups have great ideas that flounder or are too weird. If I was to start a company I’d pay the bills first with any work we could get and keep working on the “proper” game aswell.
Having said that the development world will hopefully be different (for the better!) in a few years – maybe digital distribution will rock all our worlds.
Good luck, see you in a few years for a job :)