Here's my lsnes script for Soul Blazer. It's currently set up for (U), though I have a commented line packed somewhere in there that would make it compatible with (J) instead. The lair listing code needs it, as it's the address for the pointer to the first object.
Top-left corner: Position of player
Right side: RNG, direction a certain enemy will go next
More right: List of lair information: Position, count, timer
Other odds and ends: Count of detected lairs, count of objects, RNG frame timer
This script gets false positives for lairs at times. I have tried to search through the object data some more to tighten the detection, but without success. The attempts are minimal, however, as there are no observed false negatives, and I usually can weed out the false positives while TASing.
Nothing real fancy, though. Haven't even put in the boxes that I feature in the Snes9x script. It serves well enough, though.