Weird my original reply is nowhere to be found...
I plan to use ORX which is a free open source 2d data driven engine. It can interface with C so you can use C# or C++ etc and support for that would be great. I am not sure if support through a plugin would even be possible considering how ORX works though.
I think simply being able to create the art and build frames rapidly is good enough for me if I were able to simply export those finished frames. I find the biggest time killer of all is spriting individual frames in photoshop so if this can eliminate some of that time then we are golden and I am sold. I am even willing to take finished frames exported from this program and arrange them myself in photoshop as long as I can build out all the needed frames quickly.