Wow... That news really bums me out!
Get all over the police to do a full investigation, let them know that the data is the most important. For that much to be taken it HAD to take some time so maybe someone noticed the dirtbags or their vehicle(s), heck, at that time of the morning, they should show up on cameras as well. Definitely alert the local pawnshops and music stores in case they get inquiries about gear for sale.
Damn, that really, really sucks Dave!