What wikitypes does deplate support? I'm particularly interested in DokuWiki, but I'm guessing support for the venerable MediaWiki (wikipedia...) would be cool as well :-)
deplate makes a clear distinction between block and inline elements that most wikis don't, which is why the conversion of other wiki markup only works when the input file adheres to certain rules. The way it works now, I don't think deplate can serve as a general wiki converter.
For now, deplate doesn't support any wiki markup. It does support most of rdoc (ruby documentation) though. The file input/rdoc.rb could thus serve as a starting point for implemention new input filters. There is also a file wiki-markup.rb that contains some classes that could be re-used in setting up such a filter. I think basic markup should be fairly easy to implement. Tables would require some ruby hacking. Physical text markup that deplate doesn't support could be implemented by with text styles. I'm not sure about colors.
I think somebody once tried to make a wikimedia filter but I don't know if they succeeded. I think there is a posting here in the forum somewhere and there are some references to such an effort on the Internet. Somebody once posted about an "advanced" wikimedia markup, which sounded as if the basic filter was mostly done.