Without distribution a key/value store is a hash table. To have any value added it's going to need to be a distributed key/value store. Distributed key/value stores, however, run just as well on commodity hardware. Problem is very few companies work at a scale at which per machine efficiency, power or other cost savings are going to matter; that's a very small market and one that's difficult to sell to.
On the other hand, a customized Linux distribution with a nice UI for deploying key/value stores would be a good idea.
I think even on a small scale, or perhaps that should be especially on a small scale, people could profitably look at the mysql/nosql/memcached (the latter optionally with persistence via flash) from some of the appliance vendors.
I have no financial interest or direct experience, but the data sheet on this:
http://www.schoonerinfotech.com/datasheets/Schooner_DS_Memca...
looks worthy of a closer read.
Personally, I don't use the appliances because for our extremely latency-sensitive apps we do it all from scratch for various reasons. For large scale storage we build off commodity machines. One of our prototypes runs very happily off machines from scalableinformatics.com - highly recommended.
Horses for courses and all that..