Susanna Centlivre's A Bold Stroke for a Wife is my favorite of all her plays. Two main issues have kept me from staging this one: first, it's a real tour de force for the lead actor, who gets to send up all the other lead (stock) characters--if the lead can't mimic all of them, then the show goes nowhere. Second, Centlivre was able to rely on a handful of stage tropes without minding too much about political correctness: her demographic was delighted by equal-opportunity offensiveness.
In discussing this piece in both the classroom and in theatre sessions, I've been kicking around the idea of modernizing it. "Modernizing" in the sense of how The Oregon Shakespeare Festival manages it, though: preserve most of the language, but feel free to edit/fix anachronisms/update settings/etc. For example, several of the stock characters aren't easily recognizable to the modern audience: while one can easily "translate" a changebroker to a day-trader, say, what to do with an "antiquarian"? So the trick is to figure out what abstract idea or issue the stock character is being used as shorthand for, and see if there's a substitute.
An easy one: on the 18th-century stage, the portrayal of Quakers was usually used to show a certain nervousness about religious over-enthusiasm in general. No point in taking a potshot at the fairly inoffensive Quakers in this day and age, right? But how about...corrupt televangelists? And voila, Obadiah Prim and his wife become Jim and Tammy-Faye Bakker style characters, and the lines still work, pretty much!
So that's an example of what I've been thinking about. I've gotten David sucked into it, and he's currently noodling around with one of the scenes. But in the meantime, I want to do the dramaturgy, and that requires getting a clean, digital copy into the computer, scanned from my facsimile copy of the first edition, so we can edit out the 18th-century typographical weirdness (such as the long "S" for the letter S, and the use of the dash to end almost every line), regularize the spelling, and format it like a modern script. After that, we can start playing in earnest (and I'm sure this process will keep showing up here).