A kiosk onion hidden service is now online. You can post and upload attachments. Test it out if you'd like. There's a bug report link at the bottom of the home page.
In kiosk mode you can only post anonymously. There's a help page which covers pretty much everything except for the peculiarities having to do with the kisok. If you actually go through the trouble (it's not that bad) of installing it you can very easily host your own kiosk instance (and if you run you're own version you get full functionality). Kiosk mode has a permissions system which allows for multiple passwords. There are password classes. Admins, guests, guests who can only view, guests who can post. There's a lot of options.
How to safely host a kiosk: Pay for VPS via mixed/tumbled crypto, sftp bitchan.tar.gz over tor, ssh in over tor, extract bitchan, uncomment random hidden service lines in torrc, make daemon, load random onion address in tor browser, upload archive with custom onion address, and you're set.
This kiosk instance has a 50 second post refractory period. It works with JS disabled. The kiosk disallows board and list creation, mailbox use and prevents using BM as an attachment upload method. The only things this kiosk instance allows is 1) view boards, 2) view threads (steg included), 3) make posts, and 4) submit bug reports.