Ellie you have a lot more experience than I do, so just ignore my comments if you want to, but 2 things come to mind when I read your post: 1 - No eBay seller is going to tell you their source of products knowing that you will become more of a competitor if you get that info, and 2 - eBay wholesale lots is not your best place to find products for resale.
The reason I say that is most eBay "wholesalers" are sellers who had to purchase a large quantity of the product they sell to get better prices and want a quick return on a portion of what they spent. In other words they are middle men, and you need to find a way to cut out those middle men.
For example I just received 192 dog harnesses from a supplier, other eBay resellers are advertising these at $6.95 each or large quantities for as little as $3.95 each. My total cost including shipping to Canada was about 90 cents each. I'll start my listing at $2.99 each and beat the heck out of anyone who thinks they are getting a super deal buying them for $3.95.
Ebay selling is quite a learning experience. I can say that I have spent about a year and a half studying ebay before I started selling, and have been selling for about 6 months now, and haven't really made anything lol.
I got ripped off by attemting to purchase from overseas at prices that were too good to be true. That was a hard lesson, I lost about $2500.00. The police file was a dead end.
I am not giving up though. I strongly believe that if others can do it, so can I. Ellie we just need to find the right product at the right price, and offer the right amount of customer service, and learn from others.
Just one more thing Ellie, - are you interested in wholesale dog harnesses? I have 50 available for only $2.50 each... Since no business is allowed here, I am just kidding.
Ralph