[Galaxy Tab 2 (Unified 7" + 10.1") Android Developm] BoneWithABeagle:
Well, from the top of my head I can think of three solutions...

1.) Distributed File-Sharing...

- You put your builds sorted after "CM / OMNI / AOSP / TWRP / PhilZ / CWM / ..." and P31xx/51xx into separate Syncthing shares (no, not BTSync - we don't want to use closed source software from a company of shady reputation) and make each the "master folder" (makes it read-only so no one can mess about with the master file) - i.e. "P31xx CM ##" / "P51xx CM ##" / et al" ... I think you get the idea - creates a "ton" of shares but that way you at least keep it sorted to the bare minimum.

- You make it perfectly clear that re-hosting your builds is not allowed and leads to a ban AND that participants are required to stay in the "hive" to "re-seed" the file therefore lessening the burden of bandwidth (I don't think your ISP would be happy with tons of upload on the long haul).

- You require users wanting to have the build/s to PM you via XDA (or IM) their Syncthing node ID so you can a) correlate a username to a certain node ID / b) you can invite the node into the requested share (CM / OMNI / ...)

- Isn't hassle-free for yourself, but you can at least keep track and kick "malicious entities" out of your share.

2.) Closed HTTP/FTP...

- You put your build onto a HTTP or FTP server (root or vserver) you may be able to get for cheap.

- You require users wanting to have the build/s to PM you via XDA (or IM) so you can create a user/pass combo for them to keep track of their activity (i.e. if someone "shares" the login with someone else - easy to work out if a certain login comes from a unusual IP range never seen before).

- You make it perfectly clear that rehosting / account sharing et al is a total no-go and leads to ban (for life, of course).

- Structure can be laid out like your current AF file locker.

3.) XDCC IRC bot (this will most likely keep the total n00bs (to keep it as political correct as somehow possible) far away)

- You get yourself a IRC channel on freenode or similar IRC network and make the channel only accessible to registered nicknames.

- You install a XDCC bot (Linux) and set the config to require either registered nicknames, or registered nicknames you then elevate to a certain level (Voiced / HOP / OP) yourself in your chanserv list (i.e. channel only accessible as a regged nick, download requires "Voice" or "HOP" ... that way you manage the access via the chanserv list and not via whitelists on your bot), for download access.

- You require users to get an registered nickname on the IRC network of your choice.

- You require users to PM you via XDA (or IM) their nickname so you can add the user to the whitelist of your XDCC bot.

- You may want to allow selected users to add their own XDCC bot into your channel so the burden of downloads can be shared with other bots ("untampered with" can be verified by the hash - to rule out a 3rd party may try to distributed a tampered files through their XDCC bot)

- You make it perfectly clear the re-hosting and the whole nine yard shebang is not allowed yadda yadda.

- Can contain everything (given sensical naming convention paired with reading comprehension on the user's side) on the bot so everything is up for grabs (implies that "helpers" wanting to support you by adding a bot of their own to your channel have to also have the whole thing - no partial "mirrors").

- Bonus #1: They need at least be as tech savvy as to manage to install a REAL IRC client (HexChat, mIRC, ...) as XDCC does not work via web-based frontends - that alone should sort out "31I73" from "n00B5" (if you can't manage to get a IRC client going you have no business using anything resembling a computing device).

- Bonus #2: They are in a "multiple user online chat", and in case of probs they can try to help each other in real time - plus ... annoying individuals can either be muted or banned from the channel.

If I would try to tackle a "lock releases down to a select audience" I'd either go the IRC (1st choice - worked, and still works, for distroing anime fansubs) or the Syncthing route.

In case you have questions or you want to brainstorm ideas feel free to contact me Andi.