Lots of good advise so far. Budget and space are the only limits.
I have a reasonable property size,so I built a detached 24 foot by 45 foot
garage 15 years back. It held 5 MGs ,a work bench and reasonable storage
shelves. Since it was an "A" frame design, the "attic" space held tons of
spares. (Oversize the beams to hold a hoist and create load bearing space
in the overhead) I reach the storage area by a pull down stair. The entire
place is insulated and heated with a 30 amp 220v electric overhead heater.
( Set at 40 degrees it is rarely on in the New Jersey winter climate) I
have no windows for security reasons and to hold the heat in. A side door,
an old hanging fan from some ones garbage and the double garage door
provides the needed ventilation if I run the cars inside.
About 7 years ago I ran out of space. Too many cars, so I added a 15 foot
addition making the garage 24x60. This time I added a pit ( its dangerous)
but a blessing as I am getting too old to lay on my back for extended
periods of time.
This configuration allows storage for 8 MGs, carefully placed. The back row
is three. the middle row is three. and the front row near the double door
allows two plus the work bench.
The biggest mistake I made was not to seal the concrete floor with a super
sealant. It does stain over the years. The other mistake was not to go 5
feet more to allow even more room. The neighbors already talk about this
monster, even though it is somewhat hidden behind a lot of trees. But you
can never be too rich, too skinny or have too much garage space.
There was a guy in my town who was a car collector and had oodles of money.
He built a 4500 sq foot house plus a three car garage. However he had the
basement built with a 15 foot ceiling and a circular ramp drive leading
down to the basement level. He had drains put in, a ventilation system
installed, and a pit for a hydraulic lift. I estimate he had room for
twenty cars in the basement ;Full size cars! Well the guy died before the
house was finished and the builder could not sell it with these amenities.
After a year on the market, the builder removed the circular ramp and
overhead doors in the basement, and sold the house. (probably to a family
with kids who wanted a full basketball court in the basement) Ah well it
would have been my dream house if I could have afforded it. As I said you
can never be too rich!