Implementing MI and upstreaming is something we (Codeplay) are working with as part of Hexagon remote lldb implementation work, which I gave a talk about at last years Developers meeting.
I’m not familiar with dbgp, but I think a MI plugin would be more valuable to the community as a whole. It’s widely adopted out of the box on many IDEs. Of course it doesn’t stop us implementing more protocols in the future!
We are developers of LLDB, currently keeping the Visual Studio13 build green and getting a build it up for it. The MI/Eclipse stuff will be put into review fairly soon I think. Internally we have various LLDB projects on the go.