Is there a reason you don't like the backplate? The back plate is actually a good thing because it adds support to the motherboard for these enormouse heatsinks , if you want a heatsink that does not require a backplate then you want to look for the smaller size heasinks. the backplate also provides the screw holes for attaching the heatsink in most cases.
"Almost any case with a rear 120mm fan mount location can house the Hydro Series H60 CPU cooler. As for compatibility, AMD sockets AM2 and AM3 are covered, and without having to install a custom backplate, making the H60 a great choice for any modern AMD CPU"
That is a quote directly from Corsair's website. You did not specify the type of CPU you were attempting to cool, and this was simply an example. If you would like me to find an Intel cooler, just link your board and case.
You'll need to find out the size of your case if you want to fit all-in-1 liquid coolers. Though they do not require a back plate, the large heatsinks (which usually replaces the back fan of your case) might mean they won't fit inside your case.