Since Olimex’s PCB prototype service is currently offline, I decided to try another provider for a project I’m working on. The one I settled on is OSH Park, and I have to say the online ordering process worked far more smoothly than I expected. I uploaded a *.zip file full of Gerbers exported directly from KiCad, and the system recognized everything perfectly. Here’s hoping the boards turn out equally fine.
One bit of advice: As near as I can tell, KiCad’s layer alignment targets only add extra square inches to your design for which you will be charged, so you may as well leave them off.