Stuart Marine Corp. out of Rockland Me. rents Mariners, sells new and used, as well as builds them. If you were interested in a sea trial of a keeled version, I'm sure they could set you up.
https://store.stuartmarine.com
I don't know how the cabin compares to the Capri, but the cockpit is really very nice at 7+ feet and there is room for 4 to sleep.
It sounds like you've done your research and know what you want. Good luck, the Capri is a sweet looking boat.
-Will (Dragonfly)