I can unprotect GU Edit, SCM Toolkit, SCUP, MapSide, StarForge, ProEdit 1 to 1.4.1, ToGi, etc, but it's a waste of time. GU Edit is one of the easiest, i bet I could do faster than five minutes,
, plus there are programs for GU Edit/SCM Toolkit/SCUP.
As for StarForge/SCM Draft, Heimdal and SI I would assume have their own special copies of their respective programs and wouldn't release one with the protection just disabled. There are programs that can unprotect more recent things than most unprotectors, but they're private, and I won't provide the information to manually unprotect the maps.
Right now it's easier to try to recreate a map than to unprotect them, and you can steal them without unprotecting, but I won't go into that. If you accidentally unprotected one of your own maps, you'd be pretty daft to not have a back-up, be using StarForge 2.2 or SCM Draft for automatic back-ups, and/or completely ignore back-up offers from map protectors.
If you're intent on finding out how to unprotect maps, there are indeed some scattered incomplete spec sheets of the CHK that can help you unprotect. Most of the direct guides to unprotecting were on sites that were removed by Blizzard (like Blizzhackers), but I'm sure there is some stuff possible to find. As for programs, don't expect anything more advanced SCU in English. I don't know if there are any more advanced German or Korean unprotectors.