I prefer to answer e-mail from people with real addresses. I couldn't figure
yours out.
Anyone here have experience with the dogwood as a bonsai ( American Dogwood,
Cornus florida ) ?

I haven't tried it personally, but it's been done. I think I've seen one at
International Bonsai. It has to be a large one, since the growth habit & leaf
size don't reduce much, & the flowers, of course, not at all.

Anyone know of a bonsai nursery where I could purchase one already started?

I haven't seen them for sale. Your best bet would be to buy a nursery tree or
collect one on private property.

Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)