When I bought them, I was buying from some semi-skeezy Internet retailers. The Cree LR6 was never really meant for home use. The marketing was pointing at commercial installations that ran 24/7. The Cree CR6, however, was and is widely distributed through Home Depot, rebranded under their in-house "EcoSmart" brand. (I believe.)

The 2nd-gen LR6 is much brighter than the 1st-gen (1000 lumens vs. 650 lumens) and is seemingly priced to match (roughly $0.10/lumen, then as now). I've used shopping.google.com to hunt around. The cheapest supplier is somebody I've never heard of, but well, there you go.

The 2nd-gen CR6 has better price per lumen (800 lumens for ~$60) and you can get it from Amazon (via a third-party seller), among others.

If you poke around Cree's web site, you'll see many, many variations on their products, including replacements for fluorescent tube fixtures, things you can put in 4" ceiling cans, etc. The "architectural" products are the most amazing, putting out thousands of lumens. I assume they're intended for things like atrium lobbies.