I'm deploying a couple of Cisco 6509-E with VSS using sup VS-S720-10G Sup. I need to know if there's any PoE blade currently supported by this chassis once has been converted to VSS?
No, if you are running your switches with VSS, 67xx series line cards are the only line cards that are supported in VSS. And non of those are POE.
There are no workarounds to enable POE in VSS on 67xx linecards, but here are your options:
1. Do not run VSS mode and use PoE.
2. Use PoE in a different chassis and run in VSS mode.
3. Power the PoE device locally.