a great plugin would be, if the vendor have some possibility to promote their products. For example if the vendor want to push his product always on top of the listing. He can pay a extra fee, and for example one day his product is at first place.
The extended solution is to implement an ppc (pay per click) algorithm, and the vendor can bid on a listing place.
Attached you will finde some example from Amazon and Ebay.
As per your requirement, we do not have this functionality at present. However, depending on team availability and resources we do have a plan to introduce it in near future.