How important is it for hubs to be sealed and how weak are 28H hubs?

jonaent (Jon) I'm also interested in this as I'm looking to get some DA hubs and have heard that you can get a cover for around the cones?? I remember Winston talking about this a while back I think

dura ace wheelset........large flange....3x......mavic cxp 14 deep rims......used on track only.......as new......and behold!!!!......brand new seals......180
golden nuggets....no????