Alright, I will try to formulate this as a non-shopping question... let's hope I can make it so.
I do have a board (which I can still change) which basically has 1 hole in each corner. This board, features some (user-accessible) connectors on one side (USB, ...) and now I'm looking for a way to fix this board to some mainboard.
I would like to be able to fix the board either horizontally or vertically, the required pin count is around 150 (including power and ground).
What I am looking for is a way to mount the board either way with as few additional components as possible. I also have the option to mount it to the casing in either direction but I'd rather have a version where the board is really tied to the mainboard (and to the casing).
The main question is now: Do you have another idea than using a 90° 1.27mm (0.05'') pin header?