I'm looking for a Linux terminal that is fully integrated with GNU Screen, i.e. mapping each screen buffer to a separate tab and with full scrollback support - all that inside a SSH session.
Is this currently possible?
Nope. There's currently no protocol that would allow Screen to control the terminal's tabs and to multiplex the I/O from multiple tabs over the same connection.
As ak2 said, there appears to be no such thing atm. At the moment.
That said, I looked into the very same thing (I'd love to have GNOME (or whatever) terminal on the box when I'm in front of it, but a 1:1 mapping to screen tabs when working on it remotely).
What I did find was an old bug/discussion for GNOME Terminal. Sadly, not much seems to have come of it, but at least there does seem to be some interest in such. Maybe someone will be itching enoug at some point to scratch it.