I'm wrapping up a masters in CS and already have half the credit hours needed for a degree in Human Factors. I just recently discovered how useful understanding about cognition can help someone that creates user interfaces and am thirsty for more knowledge in the area.

For me, it seems that having both a masters in Human Factors and CS would be very marketable but would there be jobs out there that would allow me to apply both?

Meaning what I would really like to do is take the requirements for some application, apply different Human Factors theories( GOMS, CE+ ) to developing the interface, maybe do cognitive walk through with users to optimize the UI, then develop the application.

Do jobs out there exist like this? The reason I ask, is because I'm wondering if most places just want you to be either a Human Factors Expert or a Developer but not both.