Seconded FYI....
The Rebel package is better suited for temp changes than the New CREE xp-e package....meaning as the LED warms up you loose less lumen output, and your chromaticity does not shift as dramatic.
All of Luxeons lines except for the new REBEL package is going obsolete, especially the luxeon style III, which most of you use... so withing 1 years time you will not be able to replace them... so try and go with the new rebel. This will not be a severe problem for these type of applications... i had two of out products go into massive redisgn because of this though, which sucked.
CREE Xp-E actually puts out more lumen output in the color ranges than Luxeon rebel, but Luxeon rebel is the king when it comes to the neutral and cool white LED.
Difference??? the cree xp-e is a little smaller than the Rebel.
and it is 1/4 the size of the Luxeon style III most of you guys use.
There is a company called FRAEN.. they make reflectors and lenses for the Cree and Rebel... I don't know if they will fit in this application because of space... but a good wide angle lens, can provide cleaner light and thus require just one Rebel instead of 3 or 4 to achieve the same Lux or foot candel numbers.
Most LED's come with things called BINS... you can control Bins for:
-Light intensity (lumens)
-Foward voltage (vf)
-Chromaticity
When you buy the LED you can specify what you want... except for CREE you cannot control Foward Voltage with them because their range is very tight from the get go.
Rebel LED's.... in my experience as of late have been a very problematic LED... when i order 80lm parts i get 40lm instead... I doubt this really concerns this application since its what we call Low power illumination... so just keep it in the back of your mind.