Installed the WSI Rack One. Had some problems lining it up but in the end, only one bolt had to go in slightly off kilter. Details here:
http://www.fordraptorforum.com/f190/rack-one-mounting-systems-wsi-37652/index24.html#post854115
http://www.fordraptorforum.com/f190/rack-one-mounting-systems-wsi-37652/index24.html#post854115