It is in an early alpha-stage, so don't expect it to be bugfree

After installation move the cursor over a directory and press Ctrl+Q to start the plugin.
Screenshots:
http://www.saydoo.net/dirinfo/pic1.png
http://www.saydoo.net/dirinfo/pic2.png
Download:
http://www.saydoo.net/dirinfo.zip
Changelog:
Version 0.1.0.57
* added color-schemes for treemap-view.
* added option to set whether the plugin should grab focus on activation
* added possibility to shade the cushions in treemap-view by last access date (older files will be shaded more, up to a max of 6 months (this is fixed at the moment))
* added possibility to load other "sub-plugins" via LoadPluginX=<pluginfile>, where X starts at 0. The subplugins will be displayed as Tabs. Still experimental.
* added toolbar to treemap-view for toggling color-schemes and opening config dialog
* replaced filesize-unit buttons with one button that opens a popup-menu
* import of colors now possible with %COMMANDER_PATH% environment variable
* minor bugs fixed
Version 0.1.0.53
* fixed bug that caused not showing K, G or M by default (thanks to vansumsen)
* color import should now work in most cases where config is redirected (thanks to vansumsen)
* added simple "Scanning"-Indicator... ([TreeView] -> Scanning)
* stability improved (better thread-handling)
Version 0.1.0.49
* filesize-display is now stored correctly
* file/directory view is now stored correctly
* fixed bug that didn't change language to english directly when selecting '< English >' from language list (thanks to petermad)
* added POLISH.LNG (thanks to fenixproductions)
Version 0.1.0.48b
* fixed bugs in Color dialog (thanks to petermad)
* added DANISH.LNG (thanks to petermad, too

* added SPANISH.LNG (thanks to Sombra)
* added totalsize display on upper right corner
Version 0.1.0.46
* added support for language files
* included english, german and french (thanks to Clo) languagefiles
* more settings will be stored (e.g. TreeView: Position and width of columns)
* initial support to load other listerplugins as subplungins in tabs (more on that later on)
* TreeMap is only rendered on demand now, causing a slightly speed up (improved since last version)
* again some more unicode support
* changing of colors / extensions possible by doubleclicking them
* minor bugfixes
Version 0.1.0.38 (Unicode)
* almost full unicode support (besides entry point from Total Commander)
* complete rewrite of Scanning Thread, speedup due to not painting treemaps all the time, speeddown due to reading more info
* remembering some more stuff
* changed column "RealSize" to "Last Access"
* some minor bugfixes
Version 0.1.0.35
* added basic unicode support in TreeView mode
- fixed bug with files > 4GB (thanks to StickyNomad)
* added navigation by pressing enter or backspace key in TreeView mode
* added contextmenu in TreeView mode
Version 0.1.0.34
+ Added basic configuration dialog, although the "Remember..." function is not fully working yet. Colors may already be set (also may be imported from Total Commander)
* some minor bugfixes