Benelli made all of them. H&K was merely the importer for the M1 Super 90 for a number of years. Its more than likely that Beretta made part of the gun too. Beretta owns Benelli, Franchi, Sako, and a few others and many of them produce parts for models across the lines.
Are you an LEO, or willing to pay the $200 SBS fees? The Benelli Entry and the Remingon have 14" BBLs and are NFA firearms. I don't know how many Police forces allow privately owned short barreled shotguns to be used by their officers. Figure $750 for the Remington 11-87P and $800-1000 for the Benelli. Then add another $200 for the NFA tax stamp, plus shipping and NFA dealer fees. My prices are conservative estimates, you might be able to do better, but there is still the $200 tax on top of that.