When I saw my site mentioned, I had to reply.
I can tell you that I don't have any t-shirt guys hosting with me at this time. Most of my clients have shopping cart sites selling gifts, games, electronics and a few other products like watches, printer cartridges, whatever. No t-shirts, other than my own.
Most are using CubeCart as their carts, which I install for them free with a year's prepayment. You can easily do the install yourself, though through Fantastico.
CubeCart is fairly easy to use with size / price options. Not terribly difficult right in the admin area, but if you have hundreds of items to add at once there is a lady in Australia who has a mod for about $ 20 to make the options get added more quickly.
You can also have OSCommerce or ZenCart installed, plus AgoraCart. Agora does not have a "customer" file, so there is no login or customer history. It does take more to set up, also. You have to go into files, where with the others unless you want to change the look of the template you can do it all from the admin area.
You can read more about me in this post -
http://www.t-shirtforums.com/member-...ns/t32593.html and if you check my posts you'll see I've helped one member with a cubecart problem, and am willing to help others.
BTW, you can use anything you want for your site. I'm not selling CubeCart. But, you can be up and selling within hours with it.