DavidHC, I think that is a great summary of what we know and don't know about the jobs of the VDR - I always find your posts stimulating because they encourage me to try to learn new things. What I have come up with so far is:

A genome-wide screen for genes which may be regulated by the VDR found 229 strong candidates. Of particular interest to the NT community include genes which seem to be involved in Type 1 diabetes, multiple sclerosis, SLE, rheumatoid arthritis. Crohn's disease and a number of cancers. Here is the fairly technical link; http://genome.cshlp.org/content/20/10/1352.long.

Apart from that VDR knockout mice have been made (a knockout mouse is one in which the gene in question has been permanently inactivated). So far it seems that the mice show abnormalities of Ca metabolism (no surprise) - as far as I can see nobody has yet used them to look at other things (autoimmunity, inflammation, etc); http://www.ncbi.nlm.nih.gov/pubmed/22903507.

I will keep digging and report back if I find anything of interest.