The Ren 90 (and smaller Ren 80's) were introduced in late 1991/early 1992 (after the Kappa series of the late 1980's). They were offered in blonde oak, black ash, and the limited edition hi gloss black lacquer. They were in the Infinity product line until 1995/96, and you probably could buy a few that remained in inventory until about '98.
I dont think Nudell had much to do with the Renaissance, it was more Cary Christie's design.
I own two pairs, one in blonde oak, and I was very fortunate to find a pair in the hi gloss piano black lacquer about two years ago- they are stunning ! (no other Infinity model was ever made in the hi gloss black, which makes them very distinctive).
I love the Renaissance 90, they are truly superb speakers with great imaging and soundstage. To surpass that in the Infinity product line, you'd have to step up to the Epsilon and spend about $7000 more than the cost of the Ren 90's, as well as spending more on heavy duty amplificaton to power them.
Back in early '95, Stereophile mag had a great issue with the Epsilon on the cover, and interviews with all three founders of Infinity. Infinity, and the Renaissance is stil very popular in Germany, and some Ren's can be seen for sale on Ebay Germany.
I'm sure there are some excellent speakers being made nowadays, but my Ren 90's are keepers for life. $2K might seem expensive, but its well worth it.