i'm not gonna go commenting on short people with small bikes (logic dictates this, right?), but my eyes glance over anything smaller than a 61cm. 20grit's above is a beauty of proportionality.

My bikes on the other hand are just freakin huge:
27" Raleigh Marathon


But I think this 65cm Nobilette looks pretty good, even if it still is super tall:



But they fit me like a charm, so no complaints. My saddle comes up to a coworker's sternum. crazy.