According to the marketpress instructions:
For a custom css style, save your css file with the "MarketPress Style: NAME" header in the "/marketpress/marketpress-includes/themes/" folder and it will appear in this list so you may select it. You can also select "None" and create custom theme templates and css to make your own completely unique store design. More information on that here »
I created and customized my own style file only to realize it was lost during the latest Marketpress update
Shouldn't Marketpress store themes and customizations like every other plugin outside its own folder to avoid this situation???