So, does anyone have any bright ideas?

I don't know if this is even possible under linux's software raid, but it occurs to me that RAID is useless for normal read only operation. It would save drive wear and tear and maybe help this problem if you only mounted the RAID for read/write mounts (or if a drive fails). For read-only situations only mount one half of the mirror bypassing the RAID software entirely and keeping one drive spun down.

-Mike