Sorry for delay in replying, ok here we go!
1. Rulers. There are none currently in SC. I could add some BUT the part about showing selection size, which i think is mostly what you want:

The selection size will update as you drag and select, and you can nudge it precisely using the cursor keys and combinations of ctrl/alt/shift. You can also select preset sizes from the toolbar and edit menu, and create your favorite sizes to be shown in those menus. Hold alt while dragging an anchor to preserve aspect ratio.
I could add rulers if people think it would really be useful i just never can think of a good reason they are needed. Remember you can configure external tools from the Tool menu if you have your favorite 3rd party ruler tool. If people can tell me a good usecase for rulers i might implement them.