I believe that the 1950 R432's were in strips of at least 13. I don't know if they came any longer though. The W560's I believe were in sheets of 16 rather than strips. A few sheets sold on the bay yesterday. I'm unsure about any other issues though.
http://cgi.ebay.com/1927-W560-Baseba...item3363a97f06
http://cgi.ebay.com/1927-W560-Baseba...item3363a9d9c9
Also, I don't believe the strips start repeating themselves... Although the more popular players may have been on a strip more than once, but don't have any confirmation on that though.