depends on what you consider 'a bit larger'
there is plenty of sandwich-style cases that take SFX psu and full-length graphics cards that are rather small.
there is the Velka 7, 5.9 ltrs from the very same company, did you look at that?
or you can go a bit smaller and stick with flex ATX and get the Velka 5, 4.9 ltrs
Other options are the usual suspects:
Dan A4
SM550
Ghost S1
CusomMod SX1 (or slightly bigger SX2)
Additionally, slightly bigger than the Velka 3 is the K39, but i am not sure it will fit your desired cards either.
Personally, I would look at the Velka 5 for what you have specified, though that said, the original sandwich-style case the Dan A4 is not that much bigger than the Velka options, at 7.2 ltrs and in my opinion is still one of the best SFF cases in the category, i only recently moved from the A4 to a T1 to cool a 3950x better, otherwise, id have stuck with the A4 indefinitely.