"More and more, it sounds to me like Denon decided to cook up their own code set (rather than using the Pioneer or Panasonic codes that I think they used initially) and didn't do enough about getting the new codes into the most commonly-used databases."
Gonk you are a true company man. I hope you're on their payroll. (no harm intended)
My Dish Network user manual has 4, not 1 but 4 Denon DVD codes and one of them worked. If Dish can manage to get the codes, certainly Outlaw could have. You may not want to admit it, but Outlaw dropped the ball. If they can't access enough codes, then they should have spent $5 more for a learning remote. Poor decision for an otherwise great product, except for digitizing the SACD output. But that's a different discussion.
Thanks for your efforts to help.

The paychecks come from OGCB , not Outlaw. My point here is just that Outlaw was using one of the best sources they could for a universal remote's code database. Outlaw didn't erase a Denon code from the remote, so I have a hard time pinning this on them as an omission. On the other hand, I do agree that a learning remote would be a wise choice.