I have six folders that I want available for quick access so my workaround was to name them in such a way that they sort to the top of the folder list (eg: 01_Sent Pending Response, 02_Cust Inquiry Pending, 03_Vendor Inquiry Pending, ...). 

Alternatively you could create a tray named 01_Favorites and place your favorite folders in it.

If you already have folder names that begin with numbers then use a special character.  My default mail folder is named "!_Main Folder" insuring that it is always at the top of my folder list.

When organizing my emails, I often want to move recent messages to a subset of my 50+ folders - these are messages relating to projects I'm working on at the moment, and there are only 5 or so of those. Having the most recent 5 folders I used in a quick one-click list somewhere would greatly speed up the sorting process!