I was thinking of starting an internet based business for making custom made bongs, then I remembered that I know nothing about bong making. I too am interested in custom pipes.
I'm going to make a big Hookah that's actually a vaporiser. For the Glass Bongs, you will need to go to either a bong making company or glass blowers. If you just want a design putting onto a bong, then buy a plain bong and just paint away haha. I'm sure there are types of glass paint.