Yes! TODO ES makes custom slip covers for your sofas. These covers are made to fit the form of your sofa from front to back. You can visit them online at www.todoes.com.
There are quite a few sites on the internet that provide custom made sofa covers. Use your search engine and request those words, custom made along with sofa covers. Two that I found and thought were very good are SlipcoverShop.com, http://www.slipcovershop.com/, and SlipcoversEtc.com, http://www.slipcoversetc.com/. Custom made will probably be more expensive and may take some time to receive them but it is a good way to go if you have a specific pattern in mind that you want. If you are concerned about expense, most sofas are a standard size and you should be able to find a pre-made one to fit yours.
There are several websites that sell custom knitted covers for a coffee table. One of these websites is table-cover.com.
Licenseplates.tv is a great website to buy custom chrome vanity plates. They also sell key chains and hitch covers.
There are many stores that sell custom made posters for use in an office space. Some of them are Superstore, Target, and Wall mart. One can also purchase custom made posters online.
You can sell new leather seat covers at thrift stores, or at online stores. One of the online stores that will purchase new leather seat covers is eBay.
There are numerous companies online that sell custom flags, but the best one is The Flag Makers at http://www.the-flag-makers.com .
You got to know where to get fine linens first. There are some online who also sell custom linens. You can get these from specialty stores not just eBay or sites selling ready-made linens. I just had custom tailored linens for a custom made bed and they turned out really great.
Yes, Barnes and Noble does sell Bible covers. You can find a variety of designs and sizes at their stores or online.
You can visit www.ehubcap.com for custom whell center caps.
A number of stores sell daybed covers. Bed Bath & Beyond, Sears, Target, are possibilities. Amazon, JC Penny and Overstock also sell the daybed covers. You might also try a local drapery design company as they can make one custom fit to your bed and in a custom design, though this is the most expensive route.
In short, you can sell your own custom shirts from anywhere. I'm assuming you want to specifically sell them online? Check out www.cafepress.com for a specialised design and sell marketplace, or you could use www.ebay.com.
Custom made shirts and other handcrafts could be sold at local markets or boutiques, but a good place to start is Etsy. Etsy is an online site for handcrafters to sell their wares. The advantage is that the site is set up for small sellers, and take advantage of the custom made business with lots of photographs and communication between crafter and customer. See related links to check out the site.
There are many online shops that sell custom metal signs. Amazon.com is one of online shop that sells custom metal signs with any kind of models. You can visit www.amazon.com