Maplin in the UK (
www.maplin.co.uk and shops) stocks a 5mm red led that puts out more light per Watt than a red Luxeon, and as it is a 5mm led, it needs no additional optics and is easier to mount.
Order Code N49AT: Hyper Orange L-53SEC-H
Kingbright description: L-53SEC-H (this is Kingbright's old numbering system)
Viewing angle: 20°
Forward voltage: 2.5V
Forward current max.: 40mA
Reverse voltage max.: 5V
Wavelength @ peak : 630nm
Power dissipation PT: 150W (I suspect this should be mW)
Light output min.@ 20mA: 7000mcd
Light output typ.@ 20mA: 10000mcd
I bought a few, and the viewing angle and brightness are such that it is brighter wider than the supposedly wider N48AT
The hyper orange is pretty close to the European standard rad rear light red. - not as deep red as the US standard car rear light.
I used six of them in a dynamo powered rear light and it is amazingly bright.
You could by a cheap 2xAA led rear and replace whatever is in there with these.
Steve