They shipped my JBL 2.1 in the original box it came in. Luckily, inside JBL packed them pretty good. If that is any indication.
If you plan to Crossfire then why not just get a beefier single GPU? Makes more sense considering driver and game support lacks bad for AMD cards. IIRC 5970 still doesn't run well in Crossfire mode for some games and it's an old card.