This post of mine from 20 months ago has a link to an online source for the same type of OptiLED red LEDs I used. Interesting that the spec sheet shown claims only 35,000 hours. That's different from the 50,000 I saw from a previous online source. Oh well, 7,000 5-hour darkroom sessions will just have to do...
I chose these based on wavelength (also not listed by this vendor) and the fact they used a standard socket base, thus making them very flexible to place. I think they would work great in the Kodak bullet-style lamps if an existing filter was reworked to hold a circle of Rubylith.
These guys are pretty bright even when used individually. Six of them in a row sitting on top of my ceiling-mounted Duplex can light up my 9x11-foot space very nicely.
[Edit: After looking around a bit just now I think the bulbs referenced in the above link may have been discontinued and replaced by these even more powerful (2-watt vs 0.5-watt) Festival H13-VF versions. This link also provides a chart showing wavelengths. Interesting that the amber LEDs are rated at about the same wavelength as the Duplex sodium doublet (~589.29 nm, albeit nowhere near as tight a spread) making them possible replacements for the Kodak OC safelights, if filtered with a sheet of Amberlith.]