My personal experience has been watching notaz, of the OpenPandora scene, get various emulators running on the Open Pandora hardware (http://openpandora.org/) .. with just a little bit of support from the hardware vendor (EvilDragon, of http://dragonbox.de/) we've seen a plethora of emulators of various systems released for the platform: http://repo.openpandora.org/?page=all&subcat=Emulator&s=new
Notaz, in particular, has proven to be a veritable force in getting these old machines running on the Pandora hardware, and I'm constantly in awe of what can be done by a few motivated individuals, whose principle purpose seems not to be commercial success, necessarily, but rather: wow factor, and more in particular: what 'wow' can be brought to the community. I've come to the conclusion that if this were a commercial activity (which it is, in limited ways) instead of the community-oriented effort (which it is, in huge ways), then there wouldn't be as much progress .. but I think guys like notaz really make the headway they make because the community itself is so approachable, so willing to communicate, and so accessible to the elite individuals doing the hard work to make the community viable. Its hard to imagine something like Dolphin happening without the underworld community that supports it - and I raise my beer to the folks in this scene who work tirelessly to bring the community wonderful new products that push the limits of the hardware we've invested in, in spite of it not being mainstream.
(BTW, if you want a clear and concise insight into this scene, you need only look at notaz' own posts on various subjects - the man is a powerhouse of emulation productivity: http://boards.openpandora.org/user/76-notaz/)