[bmatheny]

There's a lot of overhead in running a MySQL instance compared with running a memcached instance (in terms of system resources, personnel, building it redundantly). I would revisit your problem and see if you can't get memcached to fit before you decide to reinvent the wheel.

If you're set on MySQL, assuming you are on Linux (or a similar platform) you should consider perhaps using BDB or MyISAM for your storage engine and just keeping the data on a ram disk. This will give you wicked fast reads.