looking for a theme for my store with product grids

I have the MarketPress eCommerce plugin as well as WPMU DEV but I'm looking for a theme for my online store that will allow customers to choose what they are looking for by category and then have the products show up in a grid instead of having to scroll constantly down the page, like it is now, with one product on top of the next. Is there a theme with a grid that I can use with this?