Yes. Pooyan is a very good idea, I think.
I am not a programmer, but I'm a decent graphic... I don't know if my help can be needed.
In any case, when I was a kid I was a big fan of Popeye. I remember I really wanted to have a port of that game on the Vic. On cartridge, maybe. I remember that the Parker Brothers port on C64 was quite bad.
A friend of mine who got the Colecovision had a better version of it.
So, Popeye would be a must, I think. A three-stages classic platform game.
Another game I loved was Jumpman
http://en.wikipedia.org/wiki/Jumpman
Well, to be honest, I played Jumpman Junior on Colecovision (at my friend's) and I loved it. I think that an expanded Vic could handle a Jumpman Junior port, what do you think about that?