Ssh – xterm equivalent that is optimized for use over VNC

tl;dr Is there a terminal emulator that uses rectangular copies for scrolling?

I'm doing a lot over work over the internet just now (hacking a program on my employer's cluster that can't be installed on my laptop), and that has caused some changes in my workflow.

Getting a ssh tunnel with X support through the firewall to the cluster is no problem, then I have a choice.

1. Open a couple of remote xterms and emacs and go to work directly

   This is simple, but I lose all my working state anytime I disconnect from the network. Having a hairtrigger C-x C-s reflex means that I don't lose any edits, but I have to manage the lifetime of long jobs with nohup or disown, and there is fair amount of setup to do every time I log back in (even after writing a couple of scripts to cover the invariant parts of the setup).

2. Run vncserver to give myself a persistent desktop

   Seems like the perfect solution to the troubles of the direct connection, but over moderate speed connections my plain-ole' xterms seem to take inordinately log to update. Watching them it doesn't seem like they are doing rectangular copies which VNC is good at (indeed it is faster to drag filled in windows around the desktop than frames). So I find myself wondering if things wouldn't be faster on a terminal emulator that uses rectangular copies for scrolling?

Aside: X is necessary as the product I'm working on uses it for display.