Looks like I will have to talk to you before I replace the windows in my house. I bought my "new" home this past summer...that said it was built in 1950 and in a historic district, meaning the windows suck, you can feel the cold outside when you are next to them. Some of them are corner windows so I am assuming these are custom and expensive. I also believe based on the design they are structural to the house, so not sure how much that would be as a cost adder. Anyway as of right now will have to live with it as I am working on other things that need updateing right now..$$$ That said this has been an interesting thread, one of the reasons I like Prime.
Do you know if your house is ballon framed?