The Ford V10 is part of the "Modular" engine series by Ford. There are two issues with spark plugs in those engines (not just the V10). First is the spark plug popping out. Most agree that was only with the 2 valve engines but dates vary on when different models moved to three valves. The following link has more information although it list car models and not engine models the last model year listed is the 2006 F150.
See
http://www.fordproblems.com/trends/triton-engine/spark-plug-ejection.shtmlThe second issue is with spark plugs breaking when removal is attempted. This affects mostly the three valve engines and was fixed with a redesign of the spark plug. There is a tool to remove the broken spark plug without removing the heads. The last model year affected was 2008. Although when talking motorhomes that would be the chassis year not the MH year.
See
http://www.fordproblems.com/trends/triton-engine/spark-plug-stuck.shtmlMike