Develop a semi-custom wordpress plugin

I need someone to create a plugin that will be potentially resold. The plugin will be for commercial photographers who need clients to securely log in to a photo collection and proof it by selecting images, adding comments and finalizing their choices. This needs to work within any modern Wordpress (v3.5 and on) theme and be able to use the built in Wordpress gallery feature (or a common free plugin feature) but have more options for a photographer.

Will be glad to provide much more detailed specs once an estimate is received.

Please show past plugin development experience if possible. Long term relationship with additional work is a strong possibility.