Firstly join tumblr, we can not work on a theme if you don't own an account. Describe the theme you would want in details. I'll gladly help you. If you're unsure on what kind of theme you want, I will give you some ideas.
Other than money, I do this for fun so I'll be able to help you even after the order is already made. :)
Make sure to contact me before you make the order.
send me details on the kind of theme you wish to have.