Impossible has some even better 600 speed monochrome film for the various SX-70 cameras and derivatives. Here is a link to this improved stuff, which I recommend very highly.
There is frequent mention of Land on the Impossible site, but nothing there that I can find about Howard Rogers, who is the person who actually invented integral film. All this doting worship of Land is starting to get old - how about some credit to the guy who invented instant color film, and then integral film? Howard Rogers is now gone, but his many inventions remain. I talked not long ago with a scientist who worked directly under Rogers, who reported to Land, and he described him as "the real genius behind Polaroid film technology" and he added "Land was like P.T Barnum, obviously very smart, and great at promoting".
Anyway I've been a fan of Rogers since the 60s when I first got my adapter for my J66 to shoot color, which was a challenge to use, and then ran out and bought the original SX70, output of which is seen here, and am still using it in 2010.http://books.google.com/books?id=EEgEAAAAMBAJ&lpg=PA74&ots=fNfs2llOQg&dq=howard%20rogers%20polaroid&pg=PA84#v=onepage&q=howard%20rogers%20polaroid&f=false
is a link to a Life Magazine article that mentions and shows Rogers.