I haven't seen such plugin (I might be wrong), and it might be interesting.
I think that your first steps should be focused on the dialog interface, how to add new regions, adjust them and then generate the html, as well as load the data back from reading the properties of an existing area.
Hooking all that into a plugin shouldn't be hard, you could take a look at the examples plugin, the image dialog or ask for specific help.
RE: New Plugin, Image MAPLINK!
I think that your first steps should be focused on the dialog interface, how to add new regions, adjust them and then generate the html, as well as load the data back from reading the properties of an existing area.
Hooking all that into a plugin shouldn't be hard, you could take a look at the examples plugin, the image dialog or ask for specific help.
Good luck