While things may have changed since we did it, we took a year-long reward trip three years ago, booked on CO miles with NW and KLM flts. We flew the first half in July 2002 (EWR-AMS-JNB) and continued on a OW RTW from there. Our RTW ended in CPT in July 2003, where we returned home on the original reward ticket. We were even able to change the date of our return flts after the first segments were flown. The whole thing was booked in maybe Jan/Feb 2002, at the 200,000 mile Easypass level.
Robin