Specific tricks:
Teleporter Action Delay
Put two teleporters 5-10 tiles away and make sure that there's nothing between them except floor so you can roll boulders across.
Behind one of them put something to be broken with a boulder, but you need to do it in a delayed fashion to have time to run away.
You need two boulders. Just push them both between the teleporters, and push one into a teleporter. The boulders will repetitively knock each other and eventually one blocks the teleporter, the other breaks whatever was there.
Potential: good
Kaboom Walk 2
Walking a Kaboom is so much less stressful, yet much more PUZZLING when done by a shadow stinker and not by you. Less danger, more puzzle -- YAY!
Potential: good
Overlapping reflectors
If two different reflectors wind up on the same tile, a shot in them will bounce straight back at the cannon/UFO/whatever.
Potential: I couldn't use it, because all setups that allowed two reflectors to BE on the same tile in the first place were PAINFULLY obvious, but who knows what others will come up with.
Boulder Block
A boulder is sitting on a button, but another boulder is approaching from the right, threatening to knock it off. No problem, just bring a boulder from the left and push it yourself. Modification of quick switch trick.
Potential: meh.
Generic ideas:
Danger Maze
A maze that has safe points but between them EVERYTHING is covered with electros and spikes. Some combinations are possible to pass, some are not. Which ones? If you're especially sadistic, consider deadends too.
Fire Guide
One cannon, one reflector, all seven pairs of teleporters in mindboggling positions. The task is to push the reflector throught teleporters in proper order to guide a shot somewhere else.
Gate Maze
Complicated gate/conveyor arrangement, all buttons... and only two (or three) boxes. Choose the right buttons!
No-Box Sokoban
A level that resembles a known Sokoban level... only without the boxes. Have a mirrored copy WITH the boxes for a shadow stinker and cover it in trees/big boxes/what not to cover it up. And then place a hex so you can't peek.
A 99x99 sokoban.
(OK, probably not)Better use of "kaboom destroys fiery stinker" trick.
Less lame "many exits, only one reachable and only with creativity" idea.