I have done that (sanding) on LEDs to improve the dispersion of the light.

I'm also working on an LED project.  Research going forward in slow
motion.  It involves buying various cheap LED light assemblies on
ebay, shipped direct from China and testing them in the van.  Here's
an example of  one that would go in the "dome" light over the
driver's door and in the westy fixture that uses 3 bulbs.
http://www.ebay.com/itm/320723356033?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
I will share my findings with the list when I have some conclusive info.

Edward

At 03:13 PM 11/25/2011, Gary Bawden wrote:
>Thanks for that link, Alistair. I haven't tried sanding the tip off, just a
>light sanding (like 10 seconds worth with 400 grit sandpaper) over the
>entire body of the LED. I'm feeling inspired by the heater control light
>discussion, so will try sanding LEDs for that application and let everyone
>know how it works.
>
>Gary