If you are looking for a unique look without spending a lot of money on multiple roof lines, build a curved roof over your house. A curved roof allows water to evenly drain off the roof, and allows you to have a curved ceiling on the inside of the house as well. This type of roof is not common so this is custom work, but using a framing method typically used for pole barns, can yield fantastic results.
This type of roof system has a few large trusses every 12 feet that will support 2×8 rafters every 16 inches on center or 2x10s every 24 inches on center. The reason that this is the ideal method of construction is that you get a very dramatic effect on the interior of the building by leaving the large trusses exposed, and keep the labor down as the purlins are installed perpendicular to the trusses. This maintains the curve of the truss.
The trusses are large laminated beams that are custom made in the factory. This means that the trusses can be curved at the factory so they are all exactly the same. One of the issues that comes about when building curved trusses is how the truss sits on the exterior walls. This issue is eliminated in the factory as the outside wall dimensions are already know so mounting blocks can be constructed that the trusses can sit on. The blocks are attached to the top plate of the exterior walls prior to setting the trusses. The trusses are then positioned with a crane on top of the blocks and mounted using extremely long timber strand screws. Pol barn nails are also toe nailed into the walls for shear strength.
Once the trusses are set, the purlins are laid out either every 16 or 24 inches on center across the entire roof. All you have to lay out is the first truss and the last truss. Snap lines connecting them to keep them perfectly straight. The overhang on the front is made by the purlins.
The rest of the roof is typical roof construction. Add the sheeting, the underlayment and the roofing material, and you have a curved roof.
This type of roof will give you tall ceilings throughout your entire house. The ceiling finish options are numerous, each with there own style and unique beauty. One of the added benefits of this type of roof is the energy efficiency of the roof line as the air movement on the interior of the house will be more natural.