Another alternative is to get a IBM ServeRAID M1015 card, "cross flash" it, then one of those expander cards p3x-749 mentioned. Connect one port to the expand card. And the 5 ports on the expander to connect to the case.
Personally, I'm using two M1015 cards (and a third one jus sitting there for future use).
Sorry to pop in with an "off topic" question but what's the benefit of if flashing the M1015 to IT mode rather than passing it through JBOD? Just because it adds another layer? (as in ties those drives to that card?)
Is there a performance difference?
Also, can you freely flash back? (I don't see why not)
Those cards appear to be quite versatile and from what I understand, reliable. Certainly affordable.