Most of the themes here on wordpress.com have clickable headers. You can experiment if you are willing to leave MistyLook:
dashboard—>appearance—>themes—>use the "live preview" option
I believe that if you buy a CSS upgrade it is possible to make the Misty Look header clickable. You can experiment with CSS for free:
I’m not sure if the Custom Design upgrade is for me. Can I try before I buy?
Yes! Go to Appearance → Custom Design in your dashboard and click the CSS tab.
Perhaps another volunteer with CSS experience would be able to tell you how to make it work?