I have considered a laser many times lol. Just trying to make due with the considerable investment I have in CNC router equipment but just from the searches I have done seems like it's not practical to do what I want with just a cnc router. I have been considering an endurance laser add on http://endurancelasers.com/
for some time but have no experience with diode lasers, seems like it wold do the job I think. My main problem is shop space, the 4x4 cnc takes up just about 75 percent of the space and the sandblaster station takes up the rest. As far as holding a mug in a 4th axis, I saw a video of a fellow who had the base of the mug in the three jaw side of the 4th axis and on the open end of the mug he had a wood blank with rubber feet that fit inside and would keep the mug supported. He was doing beer mugs with a diamond drag bit, It worked great but seemed slow and a little cumbersome ( think it was a shopbot ) and for glass mugs sandblasting is far superior I think in quality to laser or diamond drag.
Thanks for responding