<<Disclaimer: Verify this information before applying it to your situation.>>

Thanks for the many responses I received.  Here is a summarization
of the info contained in the replies.

Point 1:  A carcinogen is NOT a substance which causes cancer in everyone
every time it is ingested.  Rather...  a carcinogen is a chemical which
causes cancer in SOME people SOME fo the time.  By this measure, it would
appear that gluten IS a carcinogen of startling potency for celiacs, with a
40-100 fold increase in incidence of intestinal lymphoma.  By contrast
tobacco, which is well accepted as a carcinogen, causes only approximately a
10 fold increase in the risk of lung cancer.  (But see Point 2 below).

Point 2:  It does not appear, however, that it has been CONCLUSIVELY
established that the entire increased risk for lymphoma for celiacs is
entirely due to gluten alone and not to the celiac condition itself (i.e.,
the genetic and other factors which predispose one to celiac sprue).  That
is, it would be nice if one could say for sure that "Yes, if you NEVER eat
any gluten, your risk for intestinal lymphoma is no higher than that of the
general population".  It appears that the above MAY be true, however, one
CANNOT confidently assert that because at this point it would appear that no
controlled studies have been done that completely disentangle the effects of
the celiac condition alone from the effects of a GF diet from a non-GF (or
middlingly non-GF) diet.