Tabs grouping suggestion?

I love having many tabs and even extra windows with other tabs :-)

I use a separate window for tabs related to a particular line of
investigation across many sites. Often I have around three windows
each with from 10-20 tabs. I guess this says something about how I
multitask :-) Anyway, I have a couple of suggestions...

1. I would like some way to identify a window sort of uniquely, but in
a convenient manner, from other firefox windows. Ideally, I could
specify a tag/string so that when looking in my taskbar for which of
the firefox windows is the one I want, my eye will find it more easily
than if that window was where most of the tabs were all related, but
the last tab viewed was something completely different. That way, the
tag reminds me that I was usign that window was for topic xyz.

2. This may be a feature too far, but I was thinking would it be
useful if there was a "tab group" concept - in a single firefox
window, currently I might have 10-20 tabs, but I would like to assign
some of those tabs to a named group, others to one or more other
groups, all within the current firefox window. Obviously, if I have
more than one firefox window, all would have this capability.

I hope it goes without saying that all of that should be recoverable
in the event that firefox closes unexpectedly.

Thanks for your patience.