I have an inclination to ask someone to create one.
I have heard this line many many times in the past. GTP was a direct result of just such a discussion. 
Sorry, that was kind of mean. Seriously though, nice thought and all, but uh... not interested. I'd probably be more interested in converted CRT's or direct connect HD LCD solutions. If I want Tempest->Raster, I'll just break out my other copies and install them. 
Not familiar. No, I meant someone in the community. Never know.
and how would it differ at all from Tempest 2000 ?
Several ways. The crab craft would actually move like in the real game, vs just rocking side to side as it moves either way. Also, it wouldn't use PC graphics. And it would be coded at something like 224x256 resolution, though of course scalable. At the very least, it could be a candidate for Misfitmame.
Do you mean like the proto 2600 Tempest look?
Not really. Definitely something more complex, perhaps not 8-bit but say something in the vein of '82-83 arcade games.
Tempest is essentially like a negative. A raster version would color the tubes of a board with a thin, black or other colored line delineating them. As well, all the objects would be colored in and detailed. An analogy would be the difference between the ship in Cosmic Chasm and the ship in Xevious or Gyruss. Fire, enemy fire, and explosions would have a similar difference.
Probably the easiest way to think about it is a sort of isometric vertical shooter that's Tempest-themed.