Re: 24 or 27 ft Catamaran with cabin (afforable) exist?
Maybe a Warram Tiki? This listing is so old I doubt it's still available but it says it was listed for $9k in good shape: Scott's Boat Pages: Wharram Tiki 21 For Sale in Colorado
There's an older thread with some pictures of the interior: Wharram Tiki 8 Meter Catamaran
I don't think they're easy to find but might be what you're looking for.
HR34 & Hobie Tiger