After reaching out to Sun to work on getting my work integrated into OpenSolaris, I found that Sun was already working on this feature. Subsequently, they indicated that the code made it into some internal source code tree. As such, I am holding off on future development until I can get at that code.
However, if you are wanting to try it out, I have posted the code for others to play with. If you have a working OpenSolaris build environment, you should be able to drop in my modified zoneadm.c, run dmake all, then use the resulting zoneadm command. Alternatively, the sparc version of the zoneadm binary is also available.