I only just recently measured the LED's in my office ceiling for a tutorial on DNG camera profiles.
The reason I am curious about LEDS is
Standard soft white CFL
Expensive CFL with a CRI of 93
Regular old tungsten bulb (which we can't buy anymore)
Cree daylight LED. CRI 80
It is this last that has me interested. Note the smoothness of the spectrum. This is only CRI 80. They have a new "TW" version that they rate at CRI 93 and refer to as "full spectrum" But it isn't available in my local Home Depot yet. (It is only in California Home Depots at present.)
SoLux bulbs are neat and all, but they are very hot. Trying to put four or so SoLux bulbs in a softbox would be, um, challenging. (I can swing four 100 watt (equiv.) CFLs in a softbox. But CFLs, well...
B&H (et al.) have inexpensive small LED panels that might do for camera scanning, if I put one close to the film. But LED lights (under $1,000) have no CRI rating (nor spectral plots) I'd like to experiment with those LED panels, but I'd really like to know what I am getting. Hence, the interest in being able to do my own spectral plots.