Of course, the GM had to do without a stamp -- but he turned out to have a favourite Noble House, so I cut a (larger) stamp of that one.
And I have designated one blank book as my 'stamp log': I'll put an impression of every stamp I cut in the book, along with information on when I cut the stamp and where I got the design from. So here's the page for the Fading Suns stamps:
You can see the mecha stamp shining through the paper, even though it's pretty thick. :P