Currently there are lgl2, PCL2ED and PCL2STAT for editing Lemmings 2 levels, and while all three together do their job of allowing for editing levels, the design process is a bit inconvenient.
In the hope of making use of these three tools, I finally got around to write a program to integrate these three to make editing and playing a bit less of a hassle. It's the program that was initially to be intended as a mere stats editor and a Qt exercise, but I extended it a bit beyond that and learned quite a bit about Qt in the process.
In essence, you can open a level through a standard file dialog now, edit its statistics and then launch one of the existing editors directly with the current level. You can also playtest the level directly via Dosbox/L2, where it will be the automatically selected level upon pressing 'Play' in the L2 main menu.
Thanks to Mindless for the source code to lem2zip.

All the related files:
http://geoo.digibase.ca/L2Suite/Windows binary:
http://geoo.digibase.ca/L2Suite/L2Suite_win32.zipLinux binary:
http://geoo.digibase.ca/L2Suite/L2Suite_linux32.tarbz2Source code:
http://geoo.digibase.ca/L2Suite/L2Suite_src.tarbz2Additional Qt DLLs required for windows version:
http://geoo.digibase.ca/L2Suite/QtDlls.zip (put them into the same folder as the program)
I also did a small update on PCL2ED to cope with compressed files (thanks to Mindless for lem2zip again):
Windows binary:
http://geoo.digibase.ca/PCL2ED/PCL2ED_win32.zipLinux binary:
http://geoo.digibase.ca/PCL2ED/PCL2ED_linux32.tarbz2Windows source:
http://geoo.digibase.ca/PCL2ED/PCL2ED_src_win.zipLinux source:
http://geoo.digibase.ca/PCL2ED/PCL2ED_src_linux.tarbz2(file extension tarbz2 as for some reason files with extension tar.bz2 get messed up)
@GuyPerfect: Unrelated, but I forgot to reply in some other thread, and didn't want to bump it; but the reason I advocated publicly releasing lgl2 is that, while as you said, everyone who expressed interest might have got it, not everyone with a remote interest may have expressed it. People tend to be shy (I know it from myself).

The source could perhaps have sped me up with this a bit, but it worked out anyway.