The database that I am trying to work into a master-slave replication environment currently has a 500 GB InnoDB file. ( I think since some cleanup was done, the database no longer has that much data in it, but the InnoDB file doesn't shrink. We could dump / undump it to get a clean InnoDB, but it takes 24 hours to dump it and about that to read it in, and we can't be down for multiple days.)

If the virtual nodes are on the same hardware, you also loose the parallelization speedup and the reliability from redundancy, but you have them spread accross physical machines I presume ?

All that said, your setup is probably good enough to learn on and do some testing. I wish I had some real-world load to throw at it.

I think you are right that you could sell NDB MySQL as a service; there is a demand for it, particularly the reliability and allways-up aspects, I think. I think that for people who want more performance, you would do better selling a set of pre-configured machines to deliver to them, and some consulting time, perhaps in partnership with someone who specializes in MySQL performance tuning.

I think that could be pretty lucretive. It would all be a matter of getting the setup down pat and then finding those customers (the hard part).