Sidebr is a greasemonkey userscript that restores the Posts/Followers/Messages/Drafts/Queue sidebar back to the dashboard.
Catching Elephant is a theme by Andy Taylor

Now compatible with Tumblr’s new layout.
I was bored.
(Source: sidebr)
New features:
A quick demo of the new features.
Major update:
As always, the userscript is here.
(Btw, I might have broken manually specified sidebars. I’ve tested it up to 3 tumblelogs, but I don’t have any more to make sure, however in theory the code is sound (HAH!). Message me if it doesn’t work beyond 3 tumblelogs and mention space penguins shooting skeeball.)
(Source: sidebr)
1. To manually change which sidebar is displayed, you need to find the userscript.
Chrome: (Find the edimojgejcmdanhinedfojglhhpfebdn folder under these folders and look for the largest version number (that is 1.0_10 > 1.0_2) and find script.js)
Firefox: (Find tumblr_sidebr.user.js)
2. Open up the file in a text editor and edit the number on line 28. Then save.
var tumblelogNum = 1;
Don’t change anything else.
2b. (Chrome) Restart Chrome.
3. Reload your /dashboard.
Example:

(I have no idea where Safari keeps its userscripts. Message me and let me know!)
(This is me again assuming you Opera users know what you’re doing. ;)
(Source: sidebr)
Minor update:
As always, the userscript is here.

Informational post:
I have third-party confirmation for all browser. This works.
You can find the userscript here.
Helpful links:
(Source: sidebr)