It would be wonderful to have the ability to work on multiple windows in addition to multiple sessions. You might consider looking carefully at the text editor Kate, which is part of the KDE desktop. It has one of the very best implementations of sessions/windows I've ever seen. It is is possible to be working on one part of the file in one window, another part of the file in a split view of the same window, and a third part of the file in a completely separate window. They are all linked to the same buffer and the updates are communicated to every active view simultaneously. I was recently working on a longish LaTeX file and really enjoyed being able to work on the same file across multiple windows.

Members of the e community have been hard at work on getting the Linux version up and running. And while it is still very much beta (perhaps even alpha) quality software, it is nonetheless extremely usable. You can find 32 and 64 bit binaries here:

http://www.oak-tree.us/e-Linux/e-TexEditor.zip