Ok, I think I finally broke some "world record" (in the world of lemmings anyway) with this:
Taxing 16: Mary Poppin's Land: Save 100%
I've only verified this on the SNES version (I'll try the PC version later tonight, though the lack of savestates will make execution hell), but it should work on most versions unless the builder builds exceedingly slow.
To give you an idea, the crowd control "device" uses just 7 builders total and 4 floaters to setup. So you actually should end up with leftover builders in the end.
Well done! I was always frustrated because I couldn't find a 100% solution to that level. Now in the PC version, there are only 18 non-100%-able levels.
Here's the ultimate challenge:
Complete the whole Lemmings game, losing a total of only 75 lemmings. I am pretty certain that this is possible in the PC DOS version.
Here's where the lemmings are lost:
Fun 3: Lose 3 Fun 6: Lose 2
Fun 18: Lose 5 Tricky 15: Lose 3
Tricky 16: Lose 4 Tricky 17: Lose 2
Tricky 18: Lose 1 Tricky 23: Lose 7
Taxing 7: Lose 1 Taxing 19: Lose 5
Taxing 27: Lose 4 Taxing 28: Lose 17
Mayhem 2: Lose 1 Mayhem 5: Lose 4
Mayhem 10: Lose 4 Mayhem 19: Lose 3
Mayhem 26: Lose 5 Mayhem 29: Lose 4
Total: Lose 75