Mmm.. I suppose another way would be to divide the collection into manageable subsets of multiple smaller databases (maybe 20000 tracks per database), and modify the Empeg kernel to boot/access them using NFS -- this kind of stuff is possible inside the Hijack kernel.

Switching between subsets ("databases") would require restarting the player software only, not rebooting, but there'd still be a pause of a few seconds when switching databases.