You might want to try a 26" frame with a low center of gravity. Most of the Electra bikes are built this way (just as an example). The lower stance seems to make it easier to get a strong start, and it's less clumsy on inclined starts.
I think it's worth mentioning the psychological aspects involved. Don't let car traffic rush or pressure you into an uncomfortable start. If I have to stop on an incline, I will just let the other traffic go on by and start off when there isn't anyone waiting. It's all about enjoying the ride...no worries