No need to download third party templates.
No need to tweak the source code of templates.
All customizations can be done with the new Template Designer.
All you need is blogger in draft.
(When you log in, just replace the www.blogger.com/home with draft.blogger.com/home in the address bar)
Do have a look at the post at Blogger in draft blog.
A few screenshots here:
(click on the image to enlarge)I'm going to try this soon.
Blogger rocks \m/