Generally not a good idea. Can you convince the missus to let you put a pier right down through the roof and the room below to a concrete slab in the soil through the house, might make an intersting dinner table centre ornament.
More seriously, some people do put long piers down but they also have to be appropriately rigid. Easier and better to build a little obervatory out the back. Brendan Mitchell, I think, has some posts on pier analysis.