I don't think that anybody is working on mips16 except for me but just in case, I wanted to outline some work that is going on so that nobody else duplicates it:
1) Fix exception handling for Mips 16. Patch already pushed for review.
2) Finish up handling of large frames. 90% of code done and being tested. One more patch is needed.
3) Hard float. (mips16 has no floating point instructions so you need to switch to mip32 mode to do this). Design is mostly done. Estimate of 3-4 weeks for implementation and testing of non optimized version. Will not start on coding of this till test-suite at near to 100% passing for all of mips 16 using soft float.
4) Constant islands. Preliminary design in progress.