Yaris has the 1.5 but seems to not do any better than the Corolla's 1.8, regardless of transmission. Deeper gearing, shorter tires, or worse areodynamics? Don't remember what the 2014's Corollas are now rated at.
In the end I ran some numbers and gave up. Selling the Jetta and running the truck until some point in the future--try as I might I'm not saving money by buying a used Corolla or a used Prius; the savings on gas is eaten up by the payment. Unless if gas explodes in price I think (as bad as I feel saying it) I'm better off racking up miles on the truck. Weird. Gas prices have been going down lately, for how long I don't know, but it certainly is a good feeling...
So I didn't bother test driving anything. Bad me.