Help designing car storage barn for Porsche’s

[rower]

(If this needs to move to a different forum please do)

What’s the best building material for a car storage barn? Economical and easy?
I was thinking room enough for 10 cars but could go bigger for various reasons.

Constraints:

1. Security Perhaps it looks agricultural to blend in to community as well)
2. Fire resistance (as in an area that could get devastating fires)
3. Natural light inside would be nice.
4. Relatively inexpensive as I get no pleasure putting money into storage
5. Easy ingress/egress for cars (a line of single stalls or two deep with doors each side?)
6. How condition the facility? Moderate climate.
7. Resale site not too specific. I may not stay in this area for ever so would start economically and see how it works. So resale too.

The materials I have thought about are steel frame or concrete, poured or pre fab.
Any advantages to which and trade off with looks, security and fire resistance plus cost? Metal frame would fit the area better perhaps. Many horse buildings and farm storage in h the area.

The natural light could be from a clear story along roof if windows aren’t secure.

What type of doors?

Thanks