If you're going down the melodeon route (I very wise choice if I may say so) have a poke around here (if you haven't found it already!):

Melodeon.Net

The home page looks out of date (and it is) but the forums (fora?) have a lively bunch of contributers who'll no doubt give you any advice on the 'best instrument in the world' to quote John Spiers!

PS Don't bother with the beginner's pages it's not constructed yet:-(