You shouldn't have too much trouble finding another Ironman in the right size. It was a popular model and there are a lot of other contemporary bikes like it. Here on Bike Forums there's a Classic & Vintage For Sale forum, and a "frame doesn't fit" trade thing, and you can just check your local Craigslist market, which I assume is huge.

Bikes like yours moved away from steel soon after yours was made and after a brief time in aluminum, have been carbon fiber ever since. There are still a lot of steel bikes (like Soma, Surly, Salsa, All-City) but their advertising emphasizes tire and fender clearance, and long rides in comfort. There are some nifty exceptions though. Check out Wraith for example. Or if you want one that still has the polished style, Bianchi has a few.