Curious, did you get these performance gains with off-the-shelf Mysql+myisam, or did you consider YC company rethinkdb (http://www.rethinkdb.com/)?
I've looked into rethinkdb, but it's not quite yet ready for a bet-the-company-on-it install. We didn't order any extra $10k+ flash cards just to play around with.
The RamSan flash cards took a while to get ahold of too (the government (NSA if I recall correctly) buys them by the thousands).