That is the second most common shower set up ever used, at least west of the Rockies! The only one you find more is the just slightly older Price Pfister Windsor, and the parts are interchangeable. The only problem is, the polished brass was not so common, and I don't know if you will find that at all today. But if you can use chrome or brushed nickel, you will find it a HD, Ace Hardware, and probably the corner drug store!
You don't have any other options. The trim pieces, and the internal stems, on all showers, are unique and not interchangeable between brands. That is the handles only. You can install vrtually ANY shower head and tub spout that you would choose. Also, the drain trip lever and tub flange are in a sense " generic". There are more thatn one size of trip buckets. Since your drain just has a grid held in place by a long #10-32 screw, you can replace the grid without unscrewing the whole flange.
A good plumbing suppy store ( probably not HD) can fix you up with all those parts.