I'm surprised that H&R and Nef don't try this, seems that they are all about the one single shot, but the H&R's are 250 just for one barrel. This is an excellent idea. When I was growing up my dad had to buy a 30-30 for deer, a winchester pump 20g for duck, and a ruger 1022 for the varmints. All of which cost way more than what rossi is charging. My sons got awhile before he can hunt but I think I'll pick one up now before they change their minds and stop selling them.
I don't know why H&R and NEF don't either, maybe their too focused on the wierd stuff like the .204 ruger (which is a very cool and very wicked little round)
As I see it with this set up (with the 50 cal) you can hunt muzzle-loader season, birds with the 12 gauge, deer with the .243 with 100 gr bullets, and varmint with the .243 with 55 gr bullets. The versatility of the .243 attracted me to buy it. IMO you get 4 guns for the price of one.