Maggi, I too crochet, tat, embroider and occasionally try needlepoint lace etc.
I do the same as you - make a working copy of a pattern, so that I can mark it. I have scanned some patterns for personal use.
If you like antique crochet and tatting patterns then there is a free site of PD patterns at:
http://www.antiquepatternlibrary.org/
Mrs Beeton's Book of Needlework and Therese de Dillmont's Encyclopedia of Needlework are both available at Project Gutenberg in HTML with illustrations. There are pdf and djvu versions at The Internet Archive.
(It would be silly to put these on a Reader because the illustrations are often several pages apart from the instructions, which would be very frustrating if you were working from them.)
Iam keeping all the needlecraft books that I intend to read, or will read again. But I have plans to scan some of the ones which I use for reference only, because I can then just print off a pattern whenever I need it. This should save some space. The 'Golden Hands' and 'Stitch by Stitch' partworks of the 1970s and 1980s take up about 2 and a half feet of bookshelves and are crying out to be scanned.