Brian, didn't you put a 17" front on your DS or was it just the low fender? From what I've read no one who has done the wheel swap on the DS has also mentioned changing the fork, the rotor is the same size and as far as I know the axle and caliper are also the same. What would be an issue is putting an FX fork on a DS (or swapping to the 21" wheel) as the rotors are different sizes, so at the very least it would require some caliper adapters.
Anyone know if the DS has higher rise bars? I can only find one listed on AF1 for the S/SR. Risers are also an option, including pivoting ones that would allow you to move the bars further forward if needed.
Dogzebra, have you considered an FXS? Little bit higher seat and has the looks you're after, the 7.2kW model would be a bit faster than a 7.2 S/DS. Of course if you're looking at 14.4 models then it's not really an option, also you have slower charging and give up some storage.