I wouldn't have any problem redirecting the payload somewhere within the LinuxBIOS build, assuming the LinuxBIOS owners are cool with that paradigm.
Speaking as one I don't have an issue.
In fact thats normally how I setup my config files anyway. Most LinuxBIOS payloads are build outside of LB. I usually copy them into my target directory with my config files so that if I need to blow away my build dir and start over clean I can without nuking my payload(s).