Replaced the interior LED lights with some eBay models:
.. not quite as warm as the standard bulbs, but the "warm white" 36-1210 boards went in most of the interior fixtures, did 24-1210's in the bunks and a circular 24-5050 in the bathroom which is slightly brighter than the 36-1210.
I ended up with 2 spare 36-1210 panels if one fails plus one adapter. I did find that the electrical contact wires on the 921 adapter for the 1210 are a bit touchy - might have to tweak these a bit after I drive around with them installed (I found bending the leads away from the plug body made a good connection). For the price which was around $50 shipped I replaced all
of the interior lights plus the exterior bulb in my camper with LED's that run about .200 ma each vs 1.4 each with the original bulbs. An improvement of 7x reduced electrical usage for a similar level and quality of light compared to the basic 921 bulbs for $50 is a good upgrade in my book.