I've been using the plug in mavic converters in a 15mm XT front hub for a year without any problems. The Mavic plugs are metal, not plastic. Did a 2000 mile fully loaded tour with them in the summer and they're still going strong. Winstanleys had them cheap a while back.
Thats good to know thanks and they're only £7.19 at Winstanleys too. I prefer the idea of the solid adapter above though as should be more robust and stiffer even if a bit heavier shouldn't it - but I suppose the weakness is still the little 5mm thick q/r in the dropout of the fork ?
Old enough to know better but doesn't.
MTB :Cannondale Prophet & Pace RC200-F2
Road : Schwinn Fastback Pro
Shed art : Raleigh Dynatech Diablo