I hate to dim your lights but here is what I think.
The retail price for the average Handi let us say is $225.
The retailer will get 30% say $67. He buys the rifle from the distributor for $158.
The distributor takes 30% for overhead and profit $47. The distributor buys the rifle from the factory $111.
The factory needs at least 50% of this money for overhead, general expenses, inventory, assembly, shipping and receiving.
That leaves $55 the shareholders will want at least $5 or more for each gun.
So here we go $50 to produce the rifle. To make that cost, most of the work is let out to subcontractors, like barrels, underlugs
investment castings of actions, triggers, hammers, latches, springs and other small parts. In order to stay in business they must keep down inventory and manual labor to a minimum. To get the best prices on parts only large quantities of the same size and shape will get the lowest price. I can see a special run of a certain caliber being made if there is a commitment from the distributor. He is the one who has to lay his money on the line.
With an operation to produce a low cost rifle, too many calibers and options would overwhelm the idea. For instance an express three leaf sight would not be economical to produce, and how many of the Handi buyers, that count nickels and dimes, would spent $250 on an express sight? To add a Shilen match barrel and a custom chamber would be $265 for the barrel plus another $150 for the custom chamber. Any one spending that kind of money would want a platform other than a Handi. But then there might be fellows that would do that, but how many?
The above is perhaps not exactly what goes on at H&R, but it is fairly accurate in principle. I think you guys better hold your breath about getting your wish list filled. Why would H&R even consider making an obsolete 303Brit? Even though it is well suited for a single shot, but there is very little market for a 303.Brit? You can hardly find any bullets for this caliber. But if you want one the 7.62x39 with the .311bore is easy to rechamber. How many are buying the 7.62x39? The only way that I can see, if you want something special, is to get a suitable existing rifle rebored and pay for the modification.
The next serious question is how much quality control can H&R afford within their budget? With all due respects it is an amazing achievement that the rifles look and shoot as well as they do for the price they sell for. The rifle and action and trigger designs are a marvel of American gun making engineering. Yes they could be made better, but-----------? To add 2 hours hand labor to the cost would nearly double the price of the rifle. Would you still buy it?