Finaly happened to me -- heading north of Barstow, CA on the 15 and the engine stop light came on with the computer telling me low oil pressure.
Pulled off as soon as possible and stopped -- pressure on the gauge was down to under 20.
Oil was pooling underneath the coach and looked like it poured out.
Got all over the underskirt and still managed to spray the toad.
Had it towed (Coach-Net was great but the tow truck managed to damage both of my mirrors!) and just received a call that the problem was a failed line and will be fixed tomorrow under warranty.