I have 4 different shops on Cafepress. One shop is totally customized, two shops make use of the Cafepress templates, and one is a free, basic shop. Let's take a look.
My Basic Shop is Horriblescopes. It features a "My Life Sucks" design that goes along with the website it promotes, Horriblescopes.net. Horriblescopes is a free horoscope website I write that is of a decidedly spoof nature. The Basic Shop allows me to use any number of designs, but I can list each product only once. For example, if I list a Women's Plus Size Scoop Neck T-shirt with the "My Life Sucks" design on it, then I can't list another Women's Plus Size scoop Neck T-shirt in my Basic Shop. I can put a logo header at the top of the shop, but I can't use any kind of fun template to spruce up the shop any further. You can have as many free shops as you want. So, if you have 50 designs, you can have 50 different shops. It's a pain in the rear to keep up, though, and because your content won't be changing, it's not going to be the darling of any major search engine.
I have 2 Cafepress Premium Shops that use the Cafepress templates. The first shop is Biblical T Shirts. It features a series of t-shirts with scriptural quotes, many in multiple languages. For example, the scripture John 3:16 has designs in 16 different languages. Strangely, I have never sold an English version of this design, although I have sold it in other languages. Go figure. This shop uses a custom logo the same as the Horriblescopes shop, but because you can do so much more with the templates and customization, it looks much spiffier.
The second Premium Cafepress Shop I have is my ottoblotto shop. This was my first shop, and its focus has evolved over the years. It is about due for a facelift; I'll let you know when that happens. Anyway, it does not use a custom logo, and goes pretty straightforwardly off the template. You can see that it is possible to make a good shop using the template even if you have no HTML skills. But I think a more custom shop looks better.
My 4th Cafepress shop is the Happy Nest Site Shop. It is a shop that uses all custom stuff: custom background, colors, logo, etc. It is made to go along with another new site I am working on, The Happy Nest Site, which features bird articles, reviews, etc. It is just getting started, so there is a lot of building to do with it. Everything you read about making POD work for you says that having sites away from the POD site that offer other information and such will help drive sales your way. I guess I'll see.
So I hope this helps you if you are looking into POD sites as a way of making a few extra bucks. My advice still is that you not quit your day job just yet.