You might benefit from another product that I offer. It's a membership script plugin for Wordpress.

From what you describe, it sounds like you could offer a "lifetime membership" to your digital downloads.

The downloads would be located on a "protected" page, that only members could access.

The plugin does allow you to also charge on an ongoing basis (monthly for example), but from what you described — it sounded like the lifetime option was the best fit.

Using this plugin, would also allow you to use whatever theme you desired (such as Thesis).

I think that would work much better than Market Theme, because Market is a theme and not a plugin. So, you couldn't use another theme such as Thesis, unless you installed a second instance of Wordpress in a subfolder and setup Market theme on that installation.

This plugin is called WP-rapid-member, and is finshed and operational — however I'm still in the process of completing the sales website. (reworking some text, typos, finalizing formatting, finishing checkout process, etc.) If you'd like to take a look, be my guest.

http://www.wp-rapid-member.com

The ordering portion of the website is not active just yet, however like I said — the plugin is complete and fully functional. If you decided that it would work for you, and you'd like to order it — just let me know and we can just do the transaction through Paypal manually.

I hope this helps.

-Eli
support[at]markettheme.com