NICE! That sounds like it will do just fine. Even something barebones like you've made is 100x better than nothing.
The only thing I see it missing is some way to open a temp session.
For instance, say you have a project open with a bunch of files and you get sidetracked. You need to work on a few other unrelated files, but you don't care about the session. You don't need it saved, it doesn't have a project file, etc. It would be great if there was someway to open a temp session that closes and saves the current session / project and allows you to work on a clean slate. When you're done, switching back to the original (or another) session would just close the files and not save the session and everything else.
Although it's handy for switching between projects, I think my main desire for the feature was because I often need to edit a few files unrelated to the project and I just need a quick, temporary clean slate to work on.
Either way thanks a bunch for this. I'll play around with it a bit later.