You're talking about lower cabinets, right? (I don't see any corner cabinets for uppers in the corner kitchen) And you only need one?

I don't know what you have in the lower corner (I just see a small door) - what's in there? This is what we did with our lower corner cabinet. We put drawers in the back 25" (they pull forward to the opening and we have access to stored stuff we need, but don't use a lot), and in the opening we have a false door. it's actually a roll-out cart that has my baking stuff on it, and extra counter space for prep work.

Don't know if that'll work for you, but it's a better use of corner space than, say, a lazy susan. And a cabinet maker would definitely be willing to make something like this if you can't, yourself.

Buying unfitted cabinets for an existing kitchen may be hard to work with. Contact some cabinet builders for estimates.