Hi all. Glad to see this thread hasn't dried up yet. At the moment I'm fiddling around with Mindless's old "provisional" L2 editor, just to amuse myself. I might publish the results of my half-hearted experimenting up here - if I manage to create anything worth sharing.
I've actually already toyed with the idea of combining PCL2ED with supplemental programs to end up with a suite that taken together, has enough functionality for basic level editing. However, that turns out to not work mainly because PCL2ED is simply not good enough for real level editing. In fact, it keeps locking up my XP laptop (granted, it has one of the worst brand of graphics cards out there, so the display driver is probably at least partly to blame), and even on a better machine, I find that the inability to manipulate whole sprites rather than individual 16x8 tiles is a real roadblock to serious level editing.
Still, if you're desperate enough to consider using PCL2ED to edit levels, I can go about and see if I can whip up some quick UI for editing level stats (eg. skills etc.), so that taken together, you get enough basic functionality to (kind of) edit levels without resorting to a hex editor. Of course, given the little free time I have nowadays, I sincerely hope that GuyPerfect will beat me to it with his full-function editor.