I can provide hosting space for levels. I can provide a folder and subdomain(which you can create subfolders in it if you want) to jury with limited ftp rights(in my hosting space for them to upload the maps for voting etc. Bandwith is not a problem but hosting space is limited around 45gb(for that folder).

I also may try to put up a upload page with an interface for mappers but it is very unlikely.(if anyone knows a script for uploading/sharing big files, i can look into them.)