So I took some more photos - FWIW I was running the wide angle LEDs in the previous photos. For me at least the narrow angle LEDs were in the black sleeving.
Clear tubing with water (3/8ID 5/8OD tygon (pure zero plasticizer stuff which btw is too small for the fittings))
Evening with lights turned on, power off and then on:
http://i.imgur.com/0V7Jfl.jpg
http://i.imgur.com/ze8U6l.jpg
For reference the tube is 2ft long. The left one seems a bit brighter, I tried wiggling the right one to see if the angle was just a problem but not much changed.
Evening with lights turned off (30s exposure), power off and then on:
There is some light bleed because I left the door open, in reality the room is pretty dark, not enough to trip over but you aren't going to be reading anything.
http://i.imgur.com/kreiZl.jpg
http://i.imgur.com/I2o6Nl.jpg
In reality the exposure was too long in the 2nd photo, really it doesn't look as blindingly bright as the photo makes it out.
Clear tubing with water + Mayhems X1 Dye at recommended concentration
I won't even bother to show the daytime ones as there's almost no difference with the LED on or off.
Evening with lights turned off (30s exposure), power off and then on:
Same camera settings as before:
http://i.imgur.com/cMfFIl.jpg
http://i.imgur.com/mVuofl.jpg
Most of the red glow on the left side is actually the PSU.
So I can't recommend these when using dye, if anything it seems a lot worse than colored tube. For dark cases in dark rooms they'll work a treat though as long as you stick to clear tube and water.