I got my LEDs to replace 921s from
superbrightleds.com. They were available in "cool" or "warm". I wanted warm (slightly reddish) because that is more relaxing in the evening. The LED brightness was very close to the original 921 incandescents.
The price per bulb was half of what I saw at my dealers and at my local Camping World. I ordered 28 bulbs; shipping cost was $2.29.
One minor caveat: the LEDs came with a lump of solder on each wire which made their bases too fat to be inserted into the sockets. It was a simple matter to scrape each base with a sharp knife to make them fit.