Hi !
To be honest, i don't shoot nor develop color film (neither will i).
My understanding is that the process is "hard" (temperature control, chemical waste control, ...) and that only a very few die-hard crazy (read awesome) people will do it in their backyards.
Black & white is "easy", temperature control doesn't need to be so accurate, the wastes are relatively eco-friendly (or completly with Caffenol) and it costs 35 cents tops for 2 rolls !
"A boutique film processor" : yes and no.
I don't know how many people shoot analogue but here are the types :
- artists --> they mostly develop themselves
- hobbyists --> 50%+ will develop B&W maybe 10% color
- hipsters/lomographists --> occasional customers
- Grand ma --> well i don't know
Even if you can process any type of negative, will you be cheaper than a lab that buys chemicals in bulk, use huge tanks and underpay a photo student ? Probably not.
Ok now, all of that sounds pretty negative (!), and i'll give you that.
Your advantage is that you can supposedly produce better negatives -actually, i don't doubt it, last time i used my local lab my only reaction was "Ok, when i said B&W i meant black, grey and white" - and another source of income.
So why not canvassing the local photo shops, prove them you can handle their demands and hopefully redirect the customers to you ... Or advertise in a local paper as a part-time professional developing agent. Well you get the idea !
Disclamer : this is only my 2c as a puty human so, correct me if you think i'm wrong !