Lots of information, thank you everyone. I get the feeling this bride is not highly sensitive to gluten - though I know better than to assume of course.
The reason for my saying so is, she mentioned it very casually in an email...sort of like a "oh, yes, and by the way" type thing. If I was deadly allergic to something I would be all over it, so to speak that is.
I've been to bridal shows where I've seen other cake vendors offer gluten free samples right next to their regular cakes, and I really don't think they are operating out of a gluten-free kitchen.
But anyhow, I think from reading all your posts the first thing I need to find out is how highly allergic to gluten she is or does she simply prefer to eat gluten-free.
Clients ask about gluten free frequently, and when I have spoken to them they have never communicated how important it is that it be 100% guaranteed to be produced in a gluten free environment, they are all very casual about it. I have to think that if they truly were that allergic they would be much more exact and detailed with their expectations.
So, I will definitely first find out just what her expectations of gluten free mean.
But also, I was looking at King Arthurs gluten free yellow cake recipe http://www.kingarthurflour.com/recipes/gluten-free-yellow-cake-recipe, anyone tried it?