High availability SQL Server without Active Directory
SIOS makes an excellent product that you can use without every supported version of SQL Server and is also SANless. It does block by block transfers and David Klee is a big enough fan that he even does sessions for them, and doesn't get remuneration for it. He just loves the product that much.

I'm not sure if it meets all of your needs but it's definitely worth checking out.

http://us.sios.com/