REX for R14 is a small free plugin for AutoCAD to add some rectanlge enhancements.
It contains these functions:

Lower-left corner

Pick first point and then another to create a simple rectangle ,
If you choose to fillet it it will use current fillet radius (FILLETRAD).
It improves on AutoCAD's RECTANG command in that it ignores OSNAP mode.


Shadow

Create a rectangle with a "shadow" (will be improved soon).



Filled

Create a filled rectangle


Rotate

Rotate a rectangle enclosed selection


Windows

Create variations of elevation windows

Distances

Create a rectangle by specifying its dimensions and then its location.


Trapezoid

Create a Trapezoid . Specify both base length + its height.



Area

Calculate a rectangle area. This is done by either touching the rectangle , pointing inside it or defining a rectangle.


Closet

Create a closet - now 2 options - simple or detailed. detailed may have its door width marked




Doors

Create an elevation door easily. The doors also have the openning dirsetion marker put in layer "HIDDEN"
which may have linetype "HIDDEN" assigned.


what-If

Enter a distance and final area and REX will draw the rectangel (handy when you need to approximate a room area or dimensions)


Settings

Set some of the parameters.


Elevator Pit

Mark rectangle holes in plans.



Room Dimensioning

You can dimension a room by picking both corners and the result is "horizontal / vertical" and
below the area (the suffix must be set in settings.