I just got my new Horticulture magazine, and there is an ad for new impatiens called VIVA SunPatiens. They are supposed to be a cross between a new guinea and regular impatiens. Sounds pretty good to me - full sun and heat tolerable. It says they will be sold exclusively at Home Depot - will be interesting to see.

Here is a link if you are interested...
SunPatiens

Those are soo pretty I am gonna have to start stocking home depot soon!!!