4u case that supports XL-ATX

I am not sure if I should post this here however I am pretty sure someone here has done it before and knows the answer!

Long story short, I have 4 Radeon x290 and I bought a case which can hold up to 3. The 4th one cannot fit because of the PSU. My mobo is MSI Big Bang which is an XL-ATX mobo. So since I want to make use of all of them, I need a new case. And since I have already a rack, it would make sense to put it there as well. So i need a 4u case!

I did some dig around for finding a 4U case that supports XL-ATX but I cant find any.

Any help?