A long time ago I built a system with 10 cd drives for ripping. I realized the real bottleneck was inserting and removing the CDs. I am a programmer, so I wrote my own software to process them in batches. Workflow was basically: load 10 CDs, go to work, come home. load 10 CDs, go to sleep, Repeat. So 200 CDs only takes 10 days. Since time is not actually a constraint, I only ran one drive at a time for vibration and stability reasons (Pentium 4 was not fast enough to rip more than one at a time), and the mp3 conversions and metadata editing as a separate process on a my main machine.
While SATA multipliers are generally not considered very good/stable, they are apparently OK for single-device-access-a-a-time, which this scheme would use. If I had to rip all my disks again, I'd buy an old dell "desktop" server that has 6 or more sata ports on the motherboard. You could even buy it, use it, then sell it to recoup your money.
Good luck!