ScummVM is a Scumm emulator that sounds exactly like Scummbar. Of course, you have to actually have the game files, but once you do, ScummVM is the answer to your questions.
Also, Scumm game creation was not limited to LucasArts. A great game called Beneat a Steal Sky was another Scumm game, now released as freeware and freely available to download at the ScummVM site
here. They also have for download Flight of the Amazon Queen (I've not played this particular game).
Here's a list of the games it supports, if you can get your hands on the game itself.
Scumm, for those who don't know, is an acronym for "Script Creation Utility for Maniac Mansion", basically a way to quickly develop the game (Maniac Mansion) after the engine was created. This works for any type of "graphic text adventure" game, by which I mean games where you still interact with things by using verbs, but this time there's pictures, and you simply click on the things you want to do, like click on the word "take" at the bottom, then click on the thing you want to take. Many adventure games were created with Scumm (and it got an homage in the Monkey Island games at the Scumm bar) but alas, the adventure game has gone the way of the dodo bird that you can still download or find on eBay or something. Because Dodo birds are like that.