Craig, the Sarissa buildings don't have internal detail other than the planked flooring, but it was easy to paint up the walls and add painted fabric tatami mats. If I am playing a skirmish game with them, such as "Ronin(Yay!)," then having much more inside the buildings would be too much, I think.
That said, the Sarissa buildings are really quite nice, and I'm glad I have both companies' buildings.
Besides painting the inside, I've used corrugated cardboard to make tile roofs. They look pretty good, and it didn't take much time or effort on my part. I'm a mediocre modeler, at best, so if they turned out well, it says a lot for the original designs.
If someone was using the buildings for the Edo Era, or the Boshin War, Sarissa would fit extremely well. For the Senkoku Era, they'd do quite well as the business district of a small town.
looks at a multi-period building.