OK, I'll bite.

You are looking for a technical solution when you do not have a proper business requirement, or do not fully understand the business requirement.

You mention consolidation. How do you plan to consolidate?

- more databases per instance

- more instances per server

- more guest VM's per physical host

Each of these could work, but without knowing the type of data, your business vector or the workload of any of these databases or servers then it is impossible for us to answer.

If you have PCI-DSS compliance needs for example then you'll probably need to implement TDE, implementing that will also encrypt TempDB which would slow down access to TempDB for those other databases on that instance.

On the other hand if you pay for third party tools for backups or monitoring the more databases per instance the more value for money you get from those products - assuming you have good security models.

In terms of HA/DR, what is the required uptime of each instance and what is your budget?

I could suggest that you have geo-clustered servers with SAN replication, that would provide you with great uptime and availability. I do not know if that would work for your business though.

Database Mirroring may work, but that is being deprecated moving forward, so Availability Groups would be a better choice. I would ask you to read all the info on Availability groups (I can just imagine Grant's face here) to make sure that this would work with your database's as there are a number of caveats.

Hope that helps,

Rich