Ken Dickey wrote:
  I would appreciate either the removal of the single inheritance restriction
  [e.g. by allowing multiple PARENT clauses] or the addition of a rational of
  why such a restriction is warrented.

I strongly agree, with the additional option of dropping
inheritance entirely (which would be my preference).

  My concern is that multiple inheritance has been found quite useful, while
  simulating multiple inheritance using single inheritance is typically tedious
  and error prone.

Personally, I haven't found single or multiple inheritance
to be particularly useful, but that doesn't make the current
proposal any more palatable.  If inheritance is necessary, at
a minimum I think that the procedural form should allow multiple
inheritance as far as the predicates are concerned.

Some discussion of the rationale would be helpful no matter
which choice is made.
                                -Richard Kelsey