Need advice on a replacement stem for my mid 80's bertoni. Have destroyed three so far (110-120mm 3ttt's all), typically ripping out the threads for the clamp bolt on the first ride. Drilling through the face to pin the bars in place has been the usual temporary fix but I'd like to find something unbreakable I can really crank on. I'd prefer italian and pretty with a bit of a drop.

dang, that's extreme! I'd say avoid any more 3TTTs since they are proving unreliable. I wonder if you have the proper diameter bar in there (are you making a 26.4 stem clamp a 26.0 bar?) Otherwise I've never had a Cinelli break yet, or strip out (always grease the threads) but have had it happen to some French stems and cheepo Italian stems. If you can stand modern stems the Cinelli "Frog" seems to be popular and the detachable plate might prove stronger and less likely to strip...but I don't have first-hand experience with it.
edit: plus if you are really concerned with stripped threads something like the Frog can allow you to shoot in Helicoils to replace the aluminum threads with stainless steel, a trick that has saved countless VW engines from the scrap heap. Unfortunately you can't shoot Helicoils into a typical road stem, I've tried.

I know the modern stem designs are much stronger with the push/pull stresses being perpendicular to 2 or 4 bolts instead of inline to 1 bolt, but I really want to keep the classic look. I have a cheap and ugly zoom stem that has been reliable on another bike, but it's just too ugly and tends to raise the effective bar height. Did Cinelli, 3ttt ever make stems in chromoly versions? The ones I have broken (aside from being used when I got them) were no doubt built for the ultimate in weight savings, and a couple grams, or even kg's, doesn't make any difference to me.

sounds like you need a cinelli steel track stem. Steel, pretty, Italian, and a bit of a drop (!). You could crank until your eyes pop out.

the only real drawback is the price...

true, strong but expensive, and the fixie crowd is keeping the price high. Cinelli also made a "welded-up" stem similar to the titanium "Grammo" but made from cro-moly...not what you'd call classic looking though. Another very strong, yet light, option would be a Salsa steel road stem; but again the price will be high and they're harder to find than their mtn. bike stems (almost all are black finish, too).

A Cinelli 2A might be a good replacement.

Wow. Am I going to have problems with the new 3ttt "Record 84" stem I haven't mounted yet?

probably not, unless you're as hard on stems as "sprince" appears to be.

Whoa! Found one of the Cinelli steel track stems on ebay. Just needed to add some more digits to the max price Sweet! Might be worth it since I'll likely never part with the bike.

No, I think it's just me. But I'll be happy to "break it in" for you.