Your post intrigued me so I used Google and found some possible sources.
I have no experience with these.

Here is a link that might be useful: HD

Thank you!
Yes, I'm familiar with those, but they're still in the very early stages of development. For instance, R7S halogen tubes are thin and narrow, like 3 or 4 inch long drinking straws. The current LED replacements, though they may be appropriate electrically, are much, much thicker and often won't fit in the fixture.
I'm sure they'll be available eventually, I'm just in a hurry and would love to hear they'll be here soon.