Kadu trunk can now send and receive files. Dcc6 and Dcc7 are supported. NAT to NAT Dcc7 connections will not work (libgadu issue). I've not checked Dcc6 callback connections (public-ip to NAT). If anyone has Gadu Gadu 6.x and is behind NAT - please contact with me on Kadu forum, so we can test this too.
What is left? Notify-based questions (accept file/reject file) and merging new file transfers with old ones (like sending rest of the same file in another session).