We use a Graco Travel Lite crib. Our pattern has been discontinued but it's still in stores like BRU as are other (nicer) patterns. The Travel Lites are 30% smaller and lighter than the full size PnP units.

We have been using the TL for 3 years now and never had any issues--hotels, cruise ships, parents' house. It comes in its own carry bag but we also got a cheapie duffel bag from Target since the carry bag material is only slightly stronger than a wet t-shirt at Señor Frogs.