Barns have:

• Spacious interiors
• High centers
• Multi-angled roof
• Drafts (difficult to insulate)

Octagonal barn: 

• Historic: https://en.wikipedia.org/wiki/Harnsberger_Octagonal_Barn
• VA frontier culture: http://www.frontiermuseum.org/rentals/octagonal-barn/

[Imagine the walls with handholds, the upper levels with static belay challenges]

Bank Barns:

• Built into hillside; entrance to upper side at top floor, lower entrance accesses ground floor.
• https://en.wikipedia.org/wiki/Bank_barn
• Potentially very high interiors with exterior perceived as modest height
• Multiple levels possible and still enabling high floor to roof
• Needs section of topology to be relatively steep (e.g., steep hillside)
  • Retaining wall
  • Engineering to keep water off the wall and floors and to divert any other water around the structure
  • Construction costs typically considerably more than the costs for a self standing building
• 12" masonry walls on a free-standing structure will give most of the same thermal benefits as a 'bank' barn but without the drainage issues and expense.