Mutt,
Pending DHD's response ... the most likely width effect, at least in Oz where there is a certification implication, is at the low weight end. The Vmcg-limited V1 may go up as a result of the runway width test program for a particular type as part of the approval to operate from less that the normal geometry-limited minimum runway "standards".
This requirement was introduced years ago as part of an ICAO recommendation ... appears Oz was the only country to take the thing seriously ... I have a number of test videos showing quite alarming centreline deviations under test conditions ... all very interesting and I experienced a rapid change from non-believer to convert ...
Quite astounding re the 1st and 2nd principle nonsense ...