I've messed around with changing the unit ID to values greater than 227, and so far have only found a few effects. Hopefully I will find more. Many pages back, some guy posted a map that did this and created an arbiter cloaking field. In order to do this, click on a unit (doesn't matter what unit) and go to its properties. Find the box on the right for unit ID. If it's a marine, it should say 0, or 1 if it's a ghost. Change that to a value greater than 227 and stuff happens. Most of the time, either nothing happens or starcraft crashes, so don't get disappointed. If you find anything, please post it in this topic.
I have tested the values from 228-240, 1000-1046, and 1600-1651.

SEN used to have a big 'ol list of these things a long time ago (see here), but it got out of date from later patches and was ultimately forgotten. It'd be neat if ways could be found to get some of the funkier effects to work, albeit from different unit IDs, in the current Starcraft version.

Because this is probably the final patch of Starcraft ever coming out, I might work on this some with you when I'm bored. Now, for the "blows up as soon as game starts", does that mean it dies, or it has like a building/nuke's explosion?

Also, for the unselectable units that give vision, if the player has all vision removed via AI script, does he or she still see the unit?

Blows up meaning death. I have no idea about the vision thing. Can't test right at this moment.

Yeah, I can't either until I locate my copy of SC and reinstall. Currently it's in one of three locations each at least 45 minutes apart, and I have no idea where within two of those locations it would be. Hopefully, when I get time later today, I'll search the boxes right behind me and be able to test that for myself.