Make bonsai pots for lemon trees? I would select a different species, lemon trees, citrus, do not make good bonsai plants. I have a calamondin in a pot but its deep, I would not consider it a 'bonsai' pot.

Since I don't own but a few I can't tell you from experience but the major factor for a good pot is being "frost proof". And all that really means is that it can take heating and cooling cycles into freezing without cracking. Whatever type of clay or firing you need to do that gets weatherproof pots on the pottery side but experience/imitation will be needed on the bonsai side. I search eBay alot to see what's out there. Search online stores. Write down common dimensions, shapes and colors. I'm sure it will take several trail and error pots until you find what does and doesn't work. After that you can add the fashion to the function.

Searching easily brings up a few sites that show throwing pots on a wheel. The one below shows some very large "pots" being assembled from clay pieces. It should at least get the gears turning for you.

http://www.langbonsai.com/

This was suggested on this forum several years ago.