Yes, there is already a site about tree id. But it's general tree not specific bonsai information. I think that a website with specific information would be nice.
http://www.oplin.lib.oh.us/products/tree/index.html this is the site with general tree info
http://bonsai-bci.com/species/indexgen.html this is the website with information but with no photos.
I think it is worth the while. I find myself asking in the nature what tree is that and if it can be bonsai'd so......
Try to go to something like the first site, i mean identify by ....