Well....the good thing about Ringo's material is that the songs are not too challanging to sing; So I think he could handle a two hour show. Also one of Ringo's strengths is the ability to tell a story. He'd proven this when he done VH-1's Storytellers, so he could pace himself for a 2 hour show easily.
Seeing good ol Ring out on his own would be great!
I would love to see and hear him behind the drums for a whole show, only Ringo on the drums - with any artist/band. To me he is simply one of the best rock/pop drummers in the world, he is THE drummer. Of course I love his singing, too, he could perhaps do a few numbers from behind his kit.