I'm looking for a person who can help me building a drone. I don't wish to use ready made circuits like fight controllers available on Amazon. So, Every part of drone like motor controller, on-board power supply, flight controller etc has to be built manually. Therefor, I need help on programming the flight controller as well. I would be happy to pay for the required help.
I do not know what's you really need? If you want to build a drone, I recommend this article for you http://www.rcdronegood.com/main-fpv-drone-parts-list/, list all the parts you need before build a drone.
For flight controller you can buy a open source FC, then modify any of it to suit your own needs. Frame also can custom it, but the power system (motor, esc,props,battery), you only can do is that choose the right one on Amazon or other shops.
Above is my experiences, hope can help you.