Grateful Dead did this with "Touch of Grey" from their album In the Dark.
Not comparing The Melvins to the Grateful Dead, but at least then (Melvins top ten hit permitting) we'd probably get to see a new Melvins video next year. (new material pending)
butthole surfers did it too with 'Pepper'(?) although that may not have been 20+ years - and that song - it wasn't really like the butthole surfers of the previous years.
what was the rest of that album (Electric Larryland) like?
The rest of Electric Larryland was a lot less commercial than "Pepper" but a lot more "accessable" than their earlier stuff. I really like it, though I like nearly everything by the Buttholes.
as far as the Melvins go;
'toy' SHOULD have been their one shot at a big pop (if you will)
crossover song!. its a great hooky tune - dare i say - a "poppy" song.
i reckon 'let it all be' (at least the first half of it) is more accessible (than toy) - this chick i was spading once really liked that song - and she liked shakira and that 'put ur ass into it' song and shit like that.
As for the rest of electric larryland - i agree - it is quite good. Though i would much rather listen to some of thier older albums.
Here's a simple formula for a Melvins hit record:
Re-record 'It's Shoved' with Butch Vig. Re-title it, making it seem less offensive. I dunno, call it 'Special' or something. Whack a remix and a version of The Bloat on as B-sides. Shove it out into record stores and wait until Buzzo gets on Top Of The Pops.