Hi Rob & Welcome
You mentioned selling through various vendors - where do you plan to get the products for your website? If you plan to get them locally and list them on your site, then that seems like a lot of work (similar to listing on eBay, but also having to remove the products one sold) - or it does to me.
Here's a link to a drop shipper you may want to check out:
http://www.selfstartersweeklytips.com/wholesale.htm (they are eBay Certified).
As for affiliate programs, I generally go for the programs that payout at least 10%. NetShops is a good one to consider, because they carry some really cool (in demand) products. Here's just an example:
http://bakersracks.webservicenetwork.com/ (this is a page I created in a matter of minutes through their site - so there's no editing, no template, etc. They carry a lot more than just bakers racks - hammocks, cedar chests, patio furniture, you name it.
You can read more about that here:
The thing about affiliate programs is that there is very little work involved, compared to purchasing products and carrying an inventory - and then also shipping things out and offering customer service. With affiliate marketing, you dont have any of that. So lower profit... not really a big deal - you have a lot less time (and money!) invested. Which you can spend working the site to make more sales
Here's one of my "affiliate sites" as an example:
http://www.corkitup.com/ . All of the products came from NetShop, and so there is no "work" involved with the site outside of marketing it. When the site makes a sale, I earn 10%. My last sale was $229.71, so I earned $22.97 - just as an example.
It just may make a good compliment to your ebay listings... you could still scout products and list them on ebay, and then use that exposure on eBay's high traffic site to drive traffic to your website (which could include a combination of affiliate products & your own products)...
Just some thoughts to consider.