What about *BSD or Inferno
*BSD is a direct descendant of the original Unix V7 with all the ATT code rewritten out. Is it as vulnerable to the patent trolls as Linux or would it be a better direction to pursue than Linux?
There used to be some pretty interesting UI's on V7 and Sys V R2/3 that were not based on X. Maybe time to reinvent a couple of wheels.
Likewise, Inferno (based on Plan9) seems to be awfully free of any patents except those owned by Bell Labs and they are under a pretty open license.