I'm new to this forum so I will briefly introduce myself.
My passion for sculpting and ceramics brought me here.
This summer I met a friend from the UK who has a passion for Bonsai.
Seen my passion for ceramics and Raku, he witnessed a raku fire.
We discussed the relation of Bonsai and Raku (mainly its philosophy) and so on.
Back home I studied more about Raku and Bonsai and decided to give it a go.
I made a dozen Raku fired Bonsai pots (hand-made of course, all unique).
Selling is one thing, improving and developing another.
Anyway, if you're interested in the result, go to this webpage
Excellent idea; I have been to some raku fires myself, as my mom used to potter in pottery a little, some decades ago . Recently I have been giving raku some thought myself, doing a little course here and there and joining a raku fire to make some pots myself.
I think there would be a good market foor good quality raku-fired bonsai pots, if prooven to be fully frost resistent.
The holes issue you will have to study a little more. Talk to your friend, and maybe look at some bonsai pots. The holes you show are too small (The smallest are for the wires, and might be ok). The bigger holes really need to be counter-intuitively large. When potting bonsai, a coarse soil mixture is used, which allows for very fast draining. This should in no way result in the holes clogging up if some of the fertiliser used drains to the bottom of the pot. In order to keep the coarse substrate in the pot, little pieces of plastic mesh are used. These measure about 5*5 cm in most stores. So a hole of say 4cm across would not be considered silly.