Okay, I have Googled it, and searched on here, but I can never get this search engine to play nice, and I got nothing from Google, either. What in tarnation is a "bespoke cake"? It sounds like something out of a 17th century romance novel, but other than that, I'm clueless. I see it all the time, though!
I don't know if I'm reading this right or not, but it seems to be some sort of English Wedding cake. Check this out: http://www.thecakestore.co.uk/acatalog/Bespoke.html
It's a British term meaning custom made. It can apply to cakes, suits, anything really.
It basically means 'made to order' i.e. a unique cake crafted to the brides requirements and not just picked out of a catelog. Makes you sound a bit more 'fancy pants' if you use the term.