You can most certainly create arrays of structures, user defined included. But no, a structure cannot contain anything but simple types, and that is not likely to change any time soon. Personally, I think it is far more important to create arrays of structures than arrays within structures, but I can certainly see the benefits of both.
That's exactly what I was going to say. I want both of course, but arrays of structures is far more important to me than arrays IN structures. The workaround for the one is infinitely easier than for the other.
Oh, alarm bells going off now. You said structs may only contain simple types, and I'm assuming a struct is not a simple type. Structs in structs is something I do quite a bit, and that IS pretty important. Maybe not quite as important as arrays of structs, but up there. (Certainly more important than arrays IN structs, for example)
Same deal with strings as arrays in structs. It would be the cleanest, but no big deal until you do or even if you never do.