What would a 4,000-BM-ton warship look like in a 1799 scenario?

In a role-playing game set in 1799, what would a privately designed 4,000-BM-ton warship be like?

A very large, fast single-deck frigate, classified here as a fifth or sixth rate and, in British service, favoring long guns for range against privateers.

For this role-playing scenario, the proposed ship is a very large, fast frigate with one principal gun deck. Its gun total might approach a fourth rate, while the single-deck arrangement leads to a fifth- or sixth-rate classification in the answer. It would be a new design, rather than a razee cut down from a larger ship. Armament would depend on the intended navy: a British version would favor long guns for their range when pursuing and engaging privateers, while carronades are suggested as a possibility for an American version. The later follow-up specifies tons BM, although its tentative comparison with a named ship is unclear in the captions.