I'd like to find out the best way to get scene referred rendering in LR. I need it mostly for testing, but it may also come handy for reproductions.
That depends
In brief:
In the earliest versions of LR, the only difference between scene referred and output referred rendering was the tone curve, and you could zero that in the controls.
In later versions or LR, up to version 3, there is an added complication in the shape of the huesatmaps and look tables in camera profiles. Depending on what you're trying to achieve and how exactly you define scene referred, you might want to strip those out. That might require a custom camera profile.
In LR version 4, it's not clear - Eric Chan has hinted that there are changes in this area, but Adobe have not yet published specs for the new DNG version, which would also have specs for the new camera profiles in it. Eric's probably the only person that could give a clear answer.
Sandy