To have wholesale pricing access to most all consumer electronics products, you sign a contract with the specific company. It details what specific products you can buy (TV's and not microwaves), what the terms are (net 30, 60, 90, floorplan, etc.) how to handle warranty issues (in house service requirements?), where you can sell your products (what states), etc.
Each company handles these issues differently. In some cases, if you carry one brand, you may not be able to get another. This usually only applies to smaller dealers. This is not legal, but convenient excuses ("we have minimum quotas that you can't meet") are always available to justify doing this.
Each brand only wants so many dealers in any given area. This is to keep the (larger) dealers happy and also explains why you might not find the same model at different stores that carry the same brand. Both of these ploys reduce the consumers ability to comparison shop, keeping retail prices higher. This may not be quite as true with HDTV products, as there are only so many available in the first place.
It's very unlikely you will be able to become a dealer, unless you are willing to buy inventory & stock product. Your best bet may be to find a small dealer & set up an arrangement with them to buy & resell product, when you find a customer. Hopefully, they will give you a better deal than retail for bringing them new customers.
"better living thru modern expensive electronics"
'Better Living Through Modern, Expensive, Electronic Devices'