In addition to the Polaroid Models 240 and 350 pack-film cameras that I bought, I also acquired three other Polaroids. (Well, technically, two Polaroids and one Minolta.) They are all integral film cameras, i.e. there is no peel-away layer.
The first below is a Spectra QPS, then a Minolta Instant Pro which shot on Spectra film. Minolta licensed the technology to produce the camera, which featured more image controls than the original Spectras. Later, Polaroid would produce its own version called the Spectra Pro. Finally, the SLR 680, a descendant of the groundbreaking SX-70 (also see the Wikipedia article). The SLR 680 used a different type of film, which was not gel-based and thus was not amenable to manipulations after exposure. On the positive side, the film is faster, allowing for more flexibility in taking conditions.
Film is available from The Impossible Project.