Interesting,
I've tried to use Particl Marketplace v.3.1, and it's something you could take a look in to and get some ideas for your marketplace project.
Although, having Particl aready running with all the bells and whistles being implemented atm, and waiting in the roadmap (particl.io, I'd rather join and help this product if you have the stuff neded, then start a new one of such complexity all by myself.
Check this thread here: https://bitcointalk.org/index.php?topic=5227333.0