Ben and August’s Extended Editor (BEEMOD) & BEE2
It does indeed work; I tested it. Haven't figured out how to use puzzlemaker_load_dev though, so I just tested it with "echo test" or something.
I even tested it with the "quit" command, and it prevented the game from quitting from the main menu. I had to close it in Task Manager!
Also, does anyone know how to remove an alias without restarting the game? I've never been able to figure that one out.
At least in HL2 there was no way, short of starting a new game session or aliasing a command to something else. Maybe you can alias it to itself?
Pretty sure that would cause an infinite loop and crash the game. Also, I can't seem to figure out how puzzlemaker_save/load_dev work. It just gives me an error no matter what I put for the parameter.
But how easy would it be to modify vbsp to ignore a room containing a certain instance?
Fairly easy, I assume. Looking at the Stylechanger, that version of VBSP replaces brush entities based on their textures and nearby instances, so it should be possible.
One concern I have: I haven't been able to get puzzlemaker_load_dev to work. I posted a thread about it, but I haven't found a solution yet. Have you had any luck?
Once we know how that works, all that's left would be to bring the idea to Ben's attention to be potentially added to BEE2. Then no more restarting Portal 2 when we need an item that isn't in the palette! 
-deleted-
Once we know how that works, all that's left would be to bring the idea to Ben's attention to be potentially added to BEE2. Then no more restarting Portal 2 when we need an item that isn't in the palette!
Hi!
*brought to my attention*
This was one of the ideas I had for adding multiple items, although I didn't think about it being ignored my the compiler
this is all possible, however maybe quite time consuming, and people would have to not delete the items on accident.
If someone else wants to make this work then I'd be happy to add this option to the BEE2
the custom compiler would def aid this btw
I've read through about the trigger objects being required to touch a wall. You say all objects require this, but that's not true. Turrets only require being on a surface (which may be another puzzle object, for example, glass). Could you implement them like turrets? This would certainly help.
I've also found a bug related to the auto-orange portal. When I place a blue portal, it opens up to a "white void" under these conditions:
Auto-orange portal is on an unportalable surface, and is activated using a weighted button several times in quick succession (I did this by accident). I'm not sure if there's anything you can do about it, but it would be nice to make map-makers aware that this can happen.
There are settings to allow placement on gratings, goo, or glass, which I think are all set to True for the triggers, but not other testing elements. But there's still no feasible way to put it in midair.
I've tried to put a trigger on those, it doesn't snap to them like a cube or turret would. I actually checked my mouse position when I get a cube to snap, and copied that position for the trigger but it doesn't work.
Edit: I can't find any official place to report bugs about BEEMod, will this forum do?