I was in the exact same position as you when I ordered my iBook - I was living in Paris but wanted a British keyboard. I spoke to Apple and they told me they could indeed deliver me a new iBook with a British keyboard, but only if I wanted a stock machine - ie no building to order. As I wanted quite a few extras built in - notably Bluetooth and the largest hard drive going - this wouldn't do.
In the end I took the slightly more expensive way out and ordered the machine from the British store to be delivered to my parents' house. They then forwarded it on to me in Paris. You may have to do the same thing.
**EDIT** - By the way, I got the reply about the possible delivery from Apple UK, not Apple France. May be worth your while giving them a bell.