I've only had a couple of ideas so far:
- Inbuilt analytics - with graphs etc, available from the WP dashboard
- shortcodes for generating affiliate links (eg. [amazon asin=0123456789]image or content, or whatever[/amazon])
That's it so far, so if there's something you want to see let me know below!
I should probably mention something about the design of theme. I'm primarily a programmer, but I can do web design if I must! The theme will have some kind of "design switcher", to stop every internet marketers blog looking the same and I will be doing a couple of designs myself but help may be required on that front at a later date. The designs should be of ThemeForest standard, so don't worry about your blog looking cheap.
I look forward to hearing your ideas!