yes, xmr fork of openbazar will sure happen sooner than later. the next 6 months will be super exciting with xmr gui + database and a possible openbazar xmr fork. Still, openbazar needs some services to function. if every vendor needs to run its own node 24/7 this wont work. but i am sure this kind of services will pop up fast. An xmr openbazarr would need those services too.
a lightweight client would sure help too, once the major stuff is done