> Do I miss anything here?

Perhaps, perhaps not.

- How will you partition the data? Is this a user/dba decision or is it
something the software does by itself?
- How does the SQL compiler/relational engine know where to find a
particular piece of data? Do you partition the queries/updates as well?
- what happens if a few new machines enter the cloud? How will data get
repartitioned? what happens if a few crash?

I think that using a stable hash as partioning algorithm will go a long
way, but a clear & simple algorithm/architecture hasn't gelled in my
mind. The brute force approach of storing everything everywhere just
seems so much simpler.

Paul