[SOLVED] Case for Flex ATX Motherboard?

[YouTownsPerson]

So I have an HP rp5800, an old POS system, but I want to upgrade it into a powerful gaming PC, but my case is too small. I have measured the motherboard, which is ~9x7.5 inches, and it looks like that is Flex ATX. What I cannot find is a case that supports Flex ATX. I mean, I can, but only on non-trustworthy sites. Is there any case for my motherboard?

 

[tennis2]

Flex-ATX uses most of the same mounting hole locations of a mATX board. So a mATX case would do the trick.