Case for Nautilus?

I want to buy/build a really nice keyboard for GMK Nautilus. I've been looking for blue cases so far, but I think all of them might be to bright. Anybody knows of a case that looks good and goes well with the keycap set? Matte dark blue or grey with subtle underglow could be awesome.

I've not yet decided on a size. The only real requirement is, that parts are available to build an ISO board on it.