I'm curious why you never see Spanish tile in cooler climates. Does it have something to do with snow? This may be kind of a dumb question, but I really like the look of Spanish tile and I only see it in places like Florida and SoCal occasionally.
It has more to do with weight and distance and architecture. Tile is heavy and transportation costs dictated where it got used. The southern states have more of the right type soil to make the tile from so that's where the factories sprang up. Also, having local craftsmen who know the product and local architects who have a Spanish influence lead to more usage of a product.
For instance, there's a lot of slate roofs in New England, 'cause that's where the slate comes from.
Since the quality of clay tiles can vary widely, so have been used in northern climates whether individual products did not last like the better units. In Minnesota, A home across the street had clay roof tile that was still in supurb condition that was built in about 1920-1925. Many of the tile made in the warmer climates do have a limitation because of the local clay and the firing process, but are good enough for the local climate.
Some of the clay tile and stone roof are actually concrete roof tile, since it can be made in different colors/blends/variations and extruded in many shapes.
A roof system should designed for it, but as a roof, you should get someone to look the roof framing. For the over-all structure the extra weight is not a factor in the big picture. Foundations are not a problem because added weight actually is a benefit.