Even without boot partition support, if Haiku's able to keep my user files on a DriveEncryption'd partition and automatically decrypt it on boot (i.e. with a password prompt at some point in the boot process or immediately after), then that's good enough for me.
I think DriveEncryption needs a few tweaks now that Beta2 is out to work again, but it's been around for quite a long time. It was made by one of the foremost kernel developers who certainly knew what he was doing. I think it's based on TrueCrypt, though he may have updated it to VeraCrypt at some point...
Definitely looks interesting, and the advertised support for decrypt-on-login is exactly what I'd need. Doesn't look like it's working on x86-64; I wonder how hard that'd be to fix...
Whatever the case, thanks! I left enough room on my disk to add an encrypted partition later (and move the stuff currently in ~ over to it), so hopefully I can get up and running with this.
Probably not that hard to fix, there are a few potential issues that come to mind but all have simple solutions, if you know where to look (and if you don't, as in Freenode#haiku.)