If I wanted to create a staff with specific spells I chose myself, can you do that with the craft staves feat?
The staves section of the PRD seems to say that staves are all of specific types.
You can, but the devs suggest themed staves, and any not in the book is really up to your GM with regards to allowability and pricing.
Short of having non-spell abilities added onto the staff, the GM shoeldn't have much say on the pricing of a staff. Like wands and scrolls, the pricing formula are meant to be adhered to rather strictly.
I do agree that staves should have a theme and that the GM is the final arbiter on whether or not to allow a given staff into his game.
True. I have no idea why I typed that pricing part in there. I guess it is because of too many pricing questions on combo items.