Yes I used the Rectangles Ovals plugin to create a rectangle then rotate it and move it nto position. But if you want to resize it that is where the fun starts because it is just a polygon with four corners, you can move them all independently so it is very hard to keep proportion or angles correct.
A rectangle is four lines at right angles. To make it longer or wider you just need to be able to increase the length of two of the sides. A circle has many more "sides" so this would be harder to implement using measurements alone, but it could be done this way.
I don't know if anyone has implemented a plugin that can do this resizing. I just know dragging the nodes to new positions is very tedious especially trying to keep a circle circular. Something that let me lengthen the individual sides is a quick-and-dirty way of increasing a polygon but there may be some better option. But the Rectangles and Ovals plugin only lets me draw new ones and if the new one is the wrong size I have to start again.