I think the easiest way to do this would be to move any FID in the /drive1/fids directory to /drive0/fids on the 60GB unit (from the empeg command line), then remove the slave drive and add it to the 10GB unit. Shouldn't have to do anything else...
I don't think any database stuff is stored in /drive1, but can't check right now as my player is in what seems an eternal fsck (oh, for the love of a journalling filesystem...) Even if there were, a rebuild/sync should regenerate the DBs...

/Michael