Your options for a curved phone are limited, but LG's new G Flex 2 is up for sale on Sprint if that's what you want. This device has a 5.5-inch 1080p AMOLED that's curved like a banana. Unlike a banana, you can get it in silver or the Sprint-exclusive "Volcano Red" color.
The G Flex 2 is one of the first devices to ship with a Snapdragon 810 processor, which might be a good thing or a bad thing, depending on whom you ask. It's a little early to know if the heat issue will be a big deal or not. LG has also kept the phone flexible (that's the name after all) and engineered a better scratch-resistant coating for the back cover.
If you decide to pick up a G Flex 2, it'll cost you $199.99 with a 2-year contract. Sprint Easy Pay works out to $21.00 per month for two years.