Here's an ugly script to operate the clipboards almost as described above.
ClipStep - Control multiple clipboards using only the keyboard's Ctrl-X-C-V
You'll find the downloads and more info at
Skrommel Software.
Select some text, press Ctrl-C a couple of times to copy it to multiple new clipboards.
Now hold down Ctrl and press V repeatedly to step through the clipboards. C steps backwards.
When you've got the clipboard you want, release Ctrl to paste.
To delete a clipboard, hold down Ctrl, press V followed by X twice to delete, three times to
delete all, or once to cancel. Release Ctrl to accept.
Edit: Swapped the scroll direction, removed two bugs.
Edit: Updated to v1.1: Changed the ordering and naming of the clips, removed the empty Cancel clip, keeps clips visible while scrolling. Also the non text clips now work.
Edit: Updated to v1.2: Removed a few bugs, tweaked some functions.
Skrommel