Most of the old games, demos, and tutorials that were ever uploaded to the Game Maker forums are still available here. Just be be careful when launching any executables. Malware could be lurking in some of these files.
This is actually such a brilliant resource. Didn't know it existed. Within minutes I found one that appears to be a reskin of the same engine I originally set out to find. Alternatively, this "samiscool" guy may be the original developer, and the one I found all those years ago was the reskin. Either way, I have found the executable, through some basic googling I found a GM7 decompiler, and my nostalgia has been satisfied (fear not, I'm not planning on stealing anybody's code).
Man what a trip. Y'all are fantastic. I look forward to spending some more time around here. Thanks team.