Thanks for that - I hadn't even contemplated them!
I've only just started building the cabinet so don't know exactly what my size limitations are, but I'm going to be pretty much following the plans from "the book".
As I wanted to keep things fairly simple, I thought it would be best to go for some coaxial (or even triaxial) units, rather than having separate bass/midrange drivers & tweeters. Parts express only seem to do one shielded coaxial unit, and that requires separate crossovers. Having said that, speakers are certainly not an area of my expertise, so I might be getting confused over what I really need......
Thanks for your help,
Richard