Terminal multiplexers are great if you're stuck in SSH, working without a window manager at all, or have a real need to share a set of terminals with multiple people at once.
But if you're hacking together a desktop environment with tiled terminals, status bars, keyboard shortcuts, dynamic or static layouts, and the ability conceal layouts on different workspaces (which is what most people's intent is when using detachment), then just get a tiling window manager already.
I agree wholeheartedly. Take what you love about tmux and extend it to include all applications. In addition to terminals (rxvt-unicode-256color) I run Firefox with Pentadactyl. With wmii (my tiling window manager of choice) I have keyboard-free navigation between vim and Firefox.
I don't buy into the remote development over SSH method. Servers with as much horsepower as my ThinkPad with an i7, SSD, and loads of RAM cost a lot, and I can't stand latency on my terminal when I'm working hard.
But if you're hacking together a desktop environment with tiled terminals, status bars, keyboard shortcuts, dynamic or static layouts, and the ability conceal layouts on different workspaces (which is what most people's intent is when using detachment), then just get a tiling window manager already.
You're reinventing the wheel.