WPMU + MarketPress + Membership - is it a good combination for a long-term running e-shopping mall?

WPMU + MarketPress + Membership - is it a good combination for a long-term running e-shopping mall?

Basically what I would like to achieve is some sort of Groupon functionality, but with the ability to assign Account managers (paid members) who will manage their own Areas (country, city or a State) - each state having it's own shops (multiple per area).

The thing is, I'm not sure marketpress + Membership are the best combinations to what I would like to achieve, mostly from structure perspective.

For example, if I am trying to create a jewelry mall and a user types in "san francisco neclases" - it would display all necklaces (all products) from San Francisco, from all the stores there (all wpmu sub-sites) - would that be possible?