Boyce Aerospace has the BT-80 fin unit (fins and fin can) in their builders kit. You can inquire as to whether they will sell you the unit separately and at what price point. Or ask if they can print only the fins without the can.
Also Aerobotix at Shapeways has BT-50,55, and I think 60 Hojo fins. Ask Kevin Cespedes at Aerobotix if he can upscale those for a BT-80 Maxi Hojo, and at what price.
Don't think either of those vendors will give you their files to upscale, though.

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I like the unusual, the off beat, the avant-garde. No 3/4 FNC for me!