Cling stamps, like acrylic stamps, can come with multiple stamps per sheet, but they are also available with one stamp per sheet (like a background stamp). And you can still use your acrylic block, that you use for your acrylic stamps. But these are made of foam and rubber instead of acrylic. I haven't used them yet, but the reviews that I have read say that the foam allows the stamp to have some cushioning and that the rubber makes for a better and crisper image. They still store flat like acrylic and are less bulky than the rubber stamps. So maybe cling stamps are the best of both worlds.
I found a great video at Inkadinkado that gives a really nice overview about Cling Stamps.
