Cody, there's another site that has the sports fan/investor in mind as well called thepit.com
It's more similar to Etopps than oneseason in that it falls more in the sports collectible category. With Etopps you get an actual card sent to you, but with The Pit, you can actually look at specific higher end cards of players on the rise (or fall) and buy, sell, or trade, without actually having to have the cards sent to you. If after investing, you do want the physical memorabilia, then you have them ship it to you as monetarily-speaking, you do own it. I never got into it, but it does fall under the sports investor category I suppose.