A Quick Win Pilot, by its very definition, is designed to run for 10-12 weeks. This is true regardless of whether SAP is involved in the BPM activities or not. Now, projects clearly vary in size and so one requirement is to propoerly scope the QWP so that the objectives are achieveable in the alloted time.
While the fundamental objectives of a QWP are centered around "Quick Win" it is possible to extend the time for the right project. We would be straying from the "Quick Win" principles and the more we elongate the schedule the more this would start to look like a traditional services exercise but it could be done.