I've perused the source code of flarum myself and concluded that flarum is from another planet, code wise. I have hacked on phpbb, wordpress, and drupal, and written php code for about 10 years now, but i'm used to code being written in a lower level / low abstraction layer way. Anyone considering just jumping into a big flarum extension project should be certain that they can handle this style of code first.
I think pirat's objection is pretty valid, that he/she would want someone who is already experienced with flarum to take this job on.
At the same time, i think spending $1000 to write an extension for a software package that's in beta is unwise as it's likely the API will change again before the final version and break the code!