Well, well, well! I came across this one purely by accident figuring I would try to go for the music first (level modifiers are usually tied to the music in some sort of array)... I got the level modifier for Ardy Lightfoot! And maybe a bit more.
Ardy Lightfoot
Level Modifier
7E0060xx
00-04, 06-09, 0B-0E, 15-19 are all working levels using this code.
12 is the password screen.
13 is the Game Over screen.
14 is the password screen already set up.
1A is the title screen.
1B-1C, 21-24, 27-28, 2B work OK. They are quick cutscene sequences. The catch is that they're not meant to loop.
1F, 26, 33 partially works... it's another cutscene. However, the graphics are a bit glitched in at least one section.
20 is the opening.
29-2A accidentally lets the camera follow the main character, although it's a functional cutscene otherwise.
I don't think anything above 37 works at all.
Any value I did not mention should not be tried, mainly because of graphical glitches.
Hmm... well, it's a start for a level modifier.