I've always wanted to try making a heatpipe myself, but I've yet to find a good method to make the wick structure... mesh is probably the most realistic choice, but sintered copper or grooves would be more effective. In any case, stumbled across this short video by Sam Bekkers and Geoff Giese today, who made a full size heatpipe for their ME412: Heat Transfer Lab class from common copper pipe and fittings. I was interested to hear what they used for the wick structure in the heatpipe stack, but I don't think they address this specifically.
How well did they do? Delta T for their heatpipe was 26.5C.
[YOUTUBE] via [Frostytech.com]