I start with good news. It's possible to change background to TypePad blogs too, and I'm working on it. And I also will make the accessories to fit better to TypePad sidebars. Some have been too wide. But new stuff is coming.
And the bad news is, that you can change the background only in TypePad Pro account. I took the two weeks trial and I'm not sure yet, if I keep it, but we will see. So I might make backgrounds for TypePad too. And also for 3 column Blogger.
But mean while, go and check new royal backgrounds, but remember, they are for princesses only. ;)