I always have my RTW tickets issued in Canada:

The last one was a *A CRWStar1 ex-ARN, priced in Swedish Kronas, on UA ticket stock, first flight on LH metal, issued in Canada and converted into Canadian Dollars.
...UA also forgot to add the USD650 sector surcharges for the SQ 77W J class flights ...

The only drawback is that you have to deal with UA to rebook flights, which can be a pain as most agents are clueless.