There are a few misconceptions popping up here. Some very very popular rounds headspace on the rim. And their accuracy is not in question. Both the .30-30 Winchester and the .45-70 Govt. (to name just two) headspace on the rim. Nearly all rounds intended for revolvers also headpace on the rim. Factories have no trouble making these rounds, and making them within accepted accuracy standards.
Also, while there is still surplus ammo for the .30-06, it is no longer considered exclusively a GI surplus caliber, being one of the premier civilian sporting rounds.
The simple fact of the matter is, no one makes a 7.62x54R sporting rifle in the US today, because it would not sell. Or sell more than a handful, which would not be enough to justify the cost of the tooling. Those few people who want a new rifle in this caliber simply buy something from overseas.
There is no US made action which is easily converted to 7.62x54R other than some single shots. It isn't worth the cost.
As to the idea of having a rifle made to take advantage of the cheap ammo, fine, rebarrel a single shot, but don't expect any US company to build a new gun for this old round. It isn't popular enough in the commercial sense.
Surplus rifles and ammo abound right now (something that wasn't the case during the Cold War years), and since the former Communists are selling them cheap, they are very popular today, especially with beginning shooters without a lot of cash to spend. But the 7.62x54R was made in this country before WWII. It failed the test of the US market. Winchester even made a rifle for it, the Model 95. Although most of them went to Russia, some were sold here. You might try finding one of them, or more likely one of the Browning reproductions, but be prepared to pay alot. Kind of negates against the cheap ammo advantage. I really can't see anyone spending $2,000+ on a rifle shooting cheap corrosive ChiCom surplus ammo in it.
Moisin Nagants and the 7.62x54R are very popular today only because they are cheap. And that ain't gonna last forever. When the supply dries up (through purchase or through UN interference) you will still be able to get ammo, but it will be at about the same cost as most other rounds.
I have nothing against the 7.62x54R, I have two rifles for it, a SVT 40 Tokarev and an M38 Moisin Nagant. But to expect US makers to do any more than a limited run chambering (at the most) is wishful thinking.