SHA512 is used for hashed password not encrypted. For encryption we are using whatever is built into the asp.net membership provider that is the base class for our mojoMembershipProvider. I believe it is based on the machinekey so sha1/AES is what I believe it uses.
I definitely think the hashed sha512 with random salt is the most secure.
I'm sorry if that doesn't meet the needs of your project but I have no near terms plans to implement any new encryption scheme in unless someone wants to sponsor it financially. BCrypt looks like an interesting project so I don't rule out ever using it but certainly not happening soon without financial incentive.
It is ok with me if you use something else for your project to meet your requirements, I do not expect mojoPortal to be the best option for every project.