Customizing MarketPress without installing another template

I already have a theme that I customized to my liking and recently installed MarketPress. However, the presentation in the default themes that come with MartketPress need to be customized.

Are there other themes specifically built to enhance the default MarketPress presentations available or would I need to start my own theme from scratch as written here: https://premium.wpmudev.org/blog/the-easy-guide-to-theming-marketpress/?

I looked into GridMarket, but it seems that it requires FrameMarket, so I am not sure if I could start from it or no.

Essentially, I am looking for some snippet I can simply plug into my already customized WP theme and MarketPress installation to enhance to default MarketPress looks.

Any help with this is much appreciated. Thanks!

P.S. For example, I am trying to achieve a store look as depicted here for the single product screenshot: http://wordpress.org/plugins/wordpress-ecommerce/screenshots/