Yes, doable but not exactly how you want it as it won't show up IN the folder but will show you everything in all sub-folders for that folder in one click.
I have to monitor several folders for system-generated errors messages but don't know when or if there will be mail in any of them. To quickly check all the sub-folders for unread mail this will do it all in one click:
Right click on Search Folders in the group containing the folder you want searched (either 'Mailbox - YourName', 'Archive Folders' or 'Personal Folders') and select 'New Search Folder'
From the 'New Folder Search' pop-up window Under 'Select a Search Folder:' scroll to the bottom and under 'Custom' click 'Create a custom Search Folder' (DO NOT CLICK 'OK' ON THE BOTTOM OF THE WINDOW YET!)
Under 'Customize Search Folder' click 'Choose'. Type in a name for your search then click 'Criteria'. From the new pop-up window 'Search Folder Critera' click on the tab 'More Choices'. Click the 'Only items that are:' box then select 'unread' from the drop-down to the right. Click OK to close this window and return to the 'Custom Search Folder' window.
Click 'Browse' to access the 'Select Folder(s)' window, click the box next to the folder(s) you want the search to look in, click the 'Search subfolders' box at the bottom and click 'OK' to close and return to the 'Customize Search Folder' window.
Click OK to create the search. You will see it under the 'Search Folders' with a count in parens of the number of unread messages. Click on the customized search name to see all individuals emails.
Hopefully I haven't completely confused you.