If I sold you a brand new Ferrari, took your money, and then tried to get a car from Ferrari - how happy would you be? If I was a Ferrari dealer who have Ferraris in inventory and sold more cars than I had in stock then I'd have a basis for claiming that I was able to deliver a car - in due course.
No it isn't you will end up with a stream of unhappy clients. Buy the stock then deliver quickly and have a reputation as a good supplier
That's the farthest thing from wise. That's exactly like saying, "well, I only make $20,000 a year and I want to buy this $400,000 house. So I will buy it, and I know I will be able to get the money later." stupid.
When a buyer wants an item, i will purchase it from a distributor immediately and then sell it to them once it is delivered. Of course, i will make up an excuse to delay the face to face transaction until i get the goods. Is it wise to dp this?