This has been a long time coming. Little girl me would have gone crazy for this in 1992.
A hacker named Ryan Souders, aka HonkeyKong, has released a patch for Maniac Mansion for the Nintendo Entertainment System that allows it to have real mouse support through the SNES Mouse via a Super Nintendo Entertainment System to Nintendo Entertainment System controller adapter.
The project's Romhacking page mentions this patch is for the North American NTSC release of Maniac Mansion. So, hamsters in the microwaves are in, but classical statues are out. The project's forum thread states this patch also works with the prototype version.
No word on whether the hamster cruelty-free European PAL version or the censorship-free prototype version is, or will be, supported, but I'll keep you posted (or most likely Jason will since I'm as common as the Nintendo PlayStation around here nowadays).
Oh, FYI, HonkeyKong made a Shadowgate mouse hack too.