i think right now try and stick with basics...your hurdle right now is not functionality but pricing. Until you can get models between $2-300 its going to be very niche. Don't try and do too much at once imo.
The hot idea is good but maybe you could add a bracket like the tlf models so it could be hung without much modification and then you could focus on sizing (nano, mid, standard) and work on getting that price down.
I think the concept is great and look forward when i can pick one of these up and not think about how to mod a $35 reactor to do something similar. $700 is just a lot to invest in order to grow chaeto....