I love the concept especially given the need in your market for storing things like snow machines, boats, rvs etc, but also for repair or general "fab shops".As long as you are seeing the demand in your specific market for these spaces, and perhaps its worth getting some leases signed up prior to breaking ground but thats a personal preference thing, I think the numbers look promising if the use case is there.

Some places you can find these are yard sales, antique stores, World Market if there’s one close to you.

It is possible to buy too many too fast and put yourself in a financial hardship.Have you ever heard of a startup store that done real good and added another store that done good?

This way the contractor isn't running to the store and waiting on anything.

The most you'll see is that it comes from some Warehouse Lender, which is usually just another bank or affiliate.

Again, the BiggerPockets store has some books on this topic, or you can learn about it by watching podcasts, reading blogs, and interacting on the forum.

When they hear Wholesaler they think in the wholesalers who supply retail stores with Products.  

I have two apartment buildings and am currently spending time looking at warehouses.

I capture the receipts as soon as I leave a home improvement store and it has saved my butt because those receipts pile up fast when you're in active renovation on multiple properties. 

They knocked down the warehouse district near downtown and built condos.