i too have been looking around for something for the past couple of months.
i havent found anything that is within my budget range at the mo but am waiting to hear back from a company - holbi.
they state they do ebay and zencart integration for £895 - waiting to find out if they can do what i want.
will let you know
i believe that ebay do something but not sure if it is only US based but i think they charge a monthly fee and then a percentage of sales.
not too keen on that.
bec