Not running Manta at the moment but it's on the menu. The demand for object storage hasn't been high enough to justify the spent time to set it up for now.
Not sure about linuxCN either. I would rather run !linux on bare metal as much as possible, and having purged most of the penguins from infrastructure it would feel a bit weird to go immediately back ;)
In addition, we also have SPARC hardware running on OpenBSD due great hardware support, including ldoms! Of course would be nice to run illumos on them too, but alas...
I'm also looking forward to further testing LinuxCN (https://github.com/joyent/linux-live/tree/linuxcn) on Triton in the near future!
Are you running Manta (https://github.com/joyent/manta) for anything? If so, is that meeting you needs for object storage?