this reminds me an old idea which i looked for long time on different OS types. i had the (un)luck to work with the sun solaris OS (sun's unix based OS), anyway, there was nice ideas there, but the one i like most was the ability to iconize running applications (correct me, but i think windows 3.1 behaved the same).
so, it truly turn your desktop into your workspace, and without the need for tabs, i was working with 30-50 files, arranged by groups (just dragging the icons anywhere i want). it was also was combined with the 'front' key on solaris keyboard (yeah, it had it special keyboard) which was super-important - you could work on an open file which cover the desktop, and you need another one, that you know you have placed on the upper-right corner of the desktop (iconized - remember?), with out the 'front' key you would need to minimize (iconize) the file you work on, then open the iconized file you need, not too great. but with the 'front' key, you would press it, and all the background icons would brought front, so you can click on one of them - genius!
long story, but when i read moe's idea i see this. very very handy indeed. let me sum up the features as i know them:
* each tab (running instance of an edited file) can be iconized into the editor own workspace (desktop like)
* you can drag the icons and put them in any order you want on the workspace, forming groups or what ever
* clicking on one, will open it to continue edit it
* 'front' key when pressed, bring all the iconized tabs to the front, allow you to click on them, while keeping the currently open tab as the background (you can click on it to return to it, or just press again on the 'front' key)
enhancements i think of:
* icons could be minimaps of the closed file, allow you see some of it contents
* selecting more than one iconized tab will open them in separate panes