PHP Developer to work within Wordpress

I need a PHP developer to work within Wordpress, coding custom features within the framework.

Custom features include user login, free and paid accounts, front end upload to a custom post, setting a price and linking that in to ecommerce (maybe woocommerce) plus more probably.

I already have a number of plugins hacked in to do most of these, but I know that if we code the functions right in, we can make it do exactly what we need it to do. I don't want someone to just install a bunch of plugins.

I would prefer to work with a developer long term - someone to bounce ideas off and continue to work with building in new features as it becomes apparent they are needed. I am a Wordpress developer myself - but what I need this to do exceeds my capabilities.