doomdoom11: GOG should make a windows version of this game....it's awesome.
GOG doesn't "make Windows (or Mac OS) versions" of any game, they just use already-available tools to get existing versions to run (DOSBox/Boxer, ScummVM, and Wine, specifically).
Since Power Pete/Mighty Mike requires a PowerPC Macintosh, it's damned near impossible to make a commercially viable solution to get the game to run on modern machines since no such solution exists that does not require a license for both Mac OS 7/8/9 and a Mac ROM.
The only "GOG-like" solution I can think of to run old Mac software on modern machines is Executor, but that only emulates a 68030 or 68040 CPU (and System 6.0.8 and 7.0 to some extent), and thus doesn't run anything that requires a PPC (like Power Pete).