I have never seen corpaci lemon for sale.
When I say interesting varieties, I mean less common. There are probably 4 mandarin varieties, 2 pommelo, 4 lemon, 4 grapefruit, and the usual limes and lemons. Pretty much if you can find the variety in a grocery store, they sell it.
So, anything that isn't common but you eat out of hand, I would like to try to grow.