MarketPress theme using Wordpress MU

I have MarketPress working on Wordpress MU. I have a theme, menus, and widget that I would like all sites to use when they create a new MarketPress store. Is there a way that I can setup WordPress MU and Marketpress to setup a default layout when someone register for a site. Example My current site have a nice theme, menu and sidebar widget. I want all new sites all reseller register for to have the same setup as me. The only difference will be there products