It's not until you find out that you can't eat gluten, or that you have a friend in this situation that you realise what a difficult life it can be. There's gluten in a huge range of things, including plenty that you probably wouldn't consider which means constant checking of labels, since even a very small amount can have terrible consequences if eaten. The Gluten Project aims to make life a little easier for people with this condition. Their search engine has a database of 35,000 gluten free products as certified by the American Gluten-Free Certification Organization (GFCO). That's the bit which is not good news for people in the UK since the products are all basically those you'll find in the United States. However, I'm sure that there's going to be a reasonable amount of crossover, which may at least provide some pointers for people.
The database is clear and easy to use. I did a simple search for 'cakes' and got literally dozens of results. They are classified by producer, with the products listed. A small number do give further details, but that simply takes you to another page which shows the product and a link so that you can buy it - I suspect the site makes a small amount as a result, which is fair enough. It's however something of a shame that they don't provide any more details on the producers, such as website, address and so on. This is a really disappointing oversight from an otherwise really helpful resource. Thanks to the ever wonderful and useful ResearchBuzz for giving me the headsup on this.