Together with AIST (Japan National Institute of Advanced Industrial Science and Technology) Nichia has developed a standard led for test purposes.
It can replace standard incandescent light sources and has enough light intensity in the full visible spectrum to be useful for measurements of all modern light sources. It being a extremely constant light source, I’d love to have one as an adjustment light in my integrating sphere when they are released. But I’m afraid that they will not be easily available and very expensive 
Would you guess at a price?
They probably don’t know themselves yet, but since the led has newly developed mixtures of dies and phosfors, it is extremely stabilised, and it is produced in a special housing my conservative guess is 3000 dollar.
No problem djozz.
We’ll take up a collection.
Sounds like a plan.
It would be a weird posession for a hobbyist, and if I had 3000 dollar spare, my hobby does not come to mind first I’m afraid, and if I was forced to spend it on the hobby, a spectrometer probably comes first. 
Look what I found! DATASHEETS!
Looks like they’re producing multiple models, visible in white and color, even UV in 3 different wavelengths.
Different models for Radiant Flux + Luminous Flux, and Luminous Intensity.
Check this one out… NLSL06S01A
-Michael
This will be quite an extensive set-up: Standard Led, constant current source, Peltier controller with PID regulation and 2mA supply for the temperature sensor, DMM.
Getting a bit worried about the pricing of the complete package
Oh come one man it’s Nichia, how bad can it be?
LOL!
Astronomical, that’s what!
Looks like they’ve changed the packaging up quite a bit as well.