I understand that certain kinds of plastic dishes and coverslips tolerate being processed for thin sectioning and can even be sectioned. I'm more interested in coverslips than petri dishes, but I'm open to being influenced otherwise.
Vendors are certainly welcome to respond.
Perhaps if we keep this off-list, I can just post a summary of the responses. Doug, I use Thermanox circular coverslips. They fit perfectly into 24 well tissue culture plates. They have a coating on one side for cell adhesion and they're sterile. I have used them for several cell types.