The Supermicro site lists the board as 12″ x 13″ (305mm x 330mm) in size.
Are there tower style cases that can handle that?
Thanks,
Chris.
Phanteks Enthoo Pro is the standard recommendation here. Plenty of cases advertise E-ATX support, but not all E-ATX is the same; check the dimensions.
Also be super careful about the metal standoffs mounting the motherboard to the case; SSI-EEB has a particular set of standoff locations, which doesn’t match up with most tower cases. It’s ok to not have a standoff where the motherboard has a hole (you can drill/tap the case, or just leave it unsupported). It’s definitely not ok to have a standoff where the motherboard doesn’t have a hole; that’s a fast way to kill your board.
Thanks for the tip regarding standoffs!
I haven’t been able to find the max motherboard measurements for the Phanteks Enthoo Pro, just that it supports “E-ATX, ATX, Micro ATX, SSI EEB”. Part of the reason I reached out on here, hoping to benefit from the experience of this community. 
Enthoo Pro is a hefty beast; it’ll even fit the EE-ATX X9DRi-LN4F+ (which doesn’t fit in the Rosewill L4500). Not as many drive bays as the Rosewill, though.
Fantastic, thanks again for the advice.