I'm using sort of the same setup to run the stats on BOINCstats. I have an update server that runs all the stat updates, which are then copied to two webservers (which hold their own copy of the stats in addition to the BAM! and forum databases which are master-master MySQL replication). Changed tables are copied every 30 minutes. The OS is installed on normal SATA drives, the databases run off Intel SSD's. The webservers also have a separate drive for cache which is also normal SATA. These were the only ones to break down so far. These servers now have a running time of two years. I think the major difference with you is that I use four SSD's in RAID 10 on the webservers and 8 SSD's for 2x RAID 10 on the database server. That way the wear on the SSD's is much less.
At work our read MySQL server also uses 8 Intel SSD's in RAID 10 for the database. This server is really battered but has been running without loosing a single drive for two years.
That's for some perspective.
I also have an offer to make, but since I'm in the Netherlands and you are in the US, it's not free. I have a complete 3U server gathering dust and I don't have any use for it for the foreseeable future. It has two Intel XEON's with two cores each, hardware RAID SCSI card (the old kind, not SAS), plenty of drives and even two spare SCSI drives. It only has 12GB of RAM and one of the modules is broken (the reason BOINCstats went of the NET for a couple of hours two years ago). Your costs would be adding RAM and the shipment cost, which won't be cheap (that thing almost breaks my back when lifting it). Can't give an exact number but I guestimate at least $200. This server was paid for by donations of the BOINC community so can't think of a better new home for it than another stats site. Let me know what you think.