quadbela would you be able to pull in readonly segments from SD/eMMC via some read ahead buffer?
This concept has utility for more than only disk I/O. You could also stream data over a local network to something like a Raspberry Pi. The extra CPU can be used to handle some of the backgound processing such as mixing and effects on a per-track basis. For example, if you are running several tracks in a relatively complex loop, and then you want to process the tracks with (for example) time stretching or pitch shifting then you would off-load the processing to a pi so the heavy-lifting doesn't glitch your live performance. Then hypothetically you could do tempo changes on-the-fly without burning more CPU time in the BBB. Presumably the local network buffering latency could be made small enough that response to control parameter changes is not terribly distracting.
That way a separate processor could be used as a mixer, synthesizer and and FX processor for recorded material.