Hey, it’s your system so you should house it however you want. 
Personally, I prefer the original cases for that authentic look and feel, although I think the Checkmate achieves that, too. But I don’t see much point in a larger case for the wedge Amigas unless you’re also adding a Zorro or PCI busboard. That’s what all that extra space was meant for! If there are replica original cases on the horizon I’d wait for those.
Also, unless something's changed in the last few years, I don’t think there’s been an A500-compatible tower case produced in decades (other than one-off custom ones), so finding one is going to be tough tough tough.
Yeah, I like the feel of the original 500 case. Even the 1200 case doesn't feel the same to me. But in the PC world, I have a thing for slim desktop cases. So putting the motherboard in a slim desktop case, assuming it's the right case, has the potential to be inexpensive and just as cool as the other options. Here's someone who did something like I had in mind:
https://www.youtube.com/watch?v=lu_ECEZoqawThe checkmate case would be better than that. But with the expansion bus adapter, keyboard, a few options, and shipping, it's approaching $500. That would pay for some serious upgrades. But the ability to have a zorro slot is also very attractive.
I guess I could try to track down an old 500 case and clean it up. The new ones will never yellow though. And they have a 1200 style mod-friendly window in the back under the floppy drive... and those metal screw inserts...