That would be awesome, thanks Blazr! I had a few questions for ThomasV, the original poster:

1) Is the "jsonrpc communication with Electrum servers" you refer to documented anywhere? If not, does anyone know where in the Electrum source I could look to figure it out?

2) The requirements state that the extension should "read/write the wallet on disk, using the same file format [as the Electrum client]". Could you explain the reasoning behind this (i.e. will you be editing/accessing the wallet file directly on the filesystem?)? Browser extensions usually don't write to the filesystem (and actually can't on any browser but Firefox).

Thanks again!