MythPhone was unmaintained in MythTV 0.19, 0.20 and 0.21 and grew a bit of cruft.
Shane S. of MythTV has recently begun submitting patches to get this plug-in running well again.
Of course, the problem is that we would either need to keep MythFrontend running, possibly on a different virtual desktop than the Orbiter, or we would need to create a MythPhone DCE Device specifically for MythPhone. Neither is impossible but someone would need to spend some time implementing this and be willing to maintain the code.
If anyone is up to the task, please contact me by e-mail and I'll help get you started.