I was researching ceramic insulators for hot ends and I finally found a standard ceramic part that could be usefull. They are called feedthru insulators. Here is a diagram for some feedthrough insulators produced by daburn:

10205a.jpg

Tha part I find most interesting is the female end. Two of these female parts could be used to completely insulate a heater block. I can't post a picture of the actual parts because the file is too large but you can look at them here: http://www.daburn.com/images/products/detail/10205.jpg

The specific part I find interesting is part# 10-206. Here are the dimmensions for the female end in referance to this drawing:

"H" 3.8mm
"C" 7.9mm
"B" 6.35mm
"G" 9.5mm

Based on these dimmensions, you could design a nichrome powered heater block to fit inside two of the female parts with the open ends facing each other, providing good insulation between the heatsink and the heater block. I have been looking for something like this for a while and I figured that if anyone else has similar ideas this might be helpfull.