I had the kid's grilled cheese sandwich at Wine Country Trattoria with the ladies trip.

Just asked sweetly and he was more than happy to get it for me!
That's the only table service I've tried it at, and it's about the only place I would (menu selection for kid meals is lousy for vegetarians who don't include corn syrup or HFCS in their diets (*cough* Uncrustables or other PB&J made with Smuckers jam/jelly *cough*)), but at the end of the day I'm at 100% success.
(but no, not buffets...and probably not even when ordering off the menu at Lilo and Stitch or Chip and Dale's character breakfasts, but it would be interesting to see what happened if you did WANT a kid's option at those)