What’s your budget? You can get much of what the 55 is all about from any broad bowled, thick walled, bent pot. Try spc’s pipe finder. Savinelli makes a few, many with uncoated bowls. Take out the filter to widened the airway and you’ll get in the 55’s ballpark.
If you must have a 55 lookalike Radice frequently makes a very similar pipe and they start around $200 for the rind finish. That would be a rare duck.
Typically you can commission a pipe for 200-400 depending on a whole host of things, but I don’t believe this is an easy shape to nail,...so that might be a factor, (really have no idea).
As to estates, well in the US, estate prices are often on par or just slightly below the cost of buying new from Italy. We have at least one site sponsor from whom I regularly buy Castello’s. Prices start around $196 for sea rocks and often old antiquaris. A quick peek at US vendors shows prices for similar pipes to begin around 120-150 more, for some bizarre reason. Follow the banner ads to an Italian vendor that has a new 55 for about 275 right now.