HP-1000... sorry if it's not in your price range but... HP-1000. If you like Grado I can vouch that you will get attached to that one.
http://www.ebay.com/itm/261009631714?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649#ht_500wt_1182
They are popping everywhere (but on eBay only ): , one per 1-2 week(s)... many were new old stock and sold for as high as 3500. People JUST STARTED noticing they had one they had never used / forgot about, with flats pads rotting, in their attic, and seeing they would sell very well on eBay. I got mine (actually two of them, HP1 and HP2) this way for... (hum, wanted to keep this a secret, too bad I guess) 930 and 1050 CAD (or "USD", they were converted to about the same) exactly.
I don't think "1000" headphones is such a limited number (that doesn't make them too rare), I definitely think that the price the latest (OMG NEVER USED! What) HP-1000 got sold (at such a low price! link above in my post) is great high-end audio quality for value. And not some random vintage headphone sound, but indeed a end-game SQ in a rock solid and very durable headphone (sorry I hope I'm not generating too much envy for old Grado fans). Joseph Grado can still upgrade it to you and if you come join us on the only HP-1000 thread still alive today, ChefGuru is about to make a review in which he will say that HP2i now performs at a similar level of that of a Sony R10.
Please keep in mind that I don't know if it's a truly truly high-performing headphone, but it's definitely in the line of the all time classics. And I think it still has the potential to fight it's way up to the top, for some people.
I love mine (even more so with my custom pads, don't listen to your HP1000 with anything else
lol, contact me if you want to know more), but I never compared it to any of the headphone you had like Magnums, HE-500/-6, LCD2-3, HD800, T1, etc. yet.
Someone said T50RP, I think it's very good also but can be a hassle to fine tune... in my case my mod turned to crap (sorry for bad word). But I don't think T50RP got better than a LCD2 yet and since you did owned that one I wouldn't make such suggest T50RP to you, if you want to know "What to get after LCD-2.1?".
Although like wje said, some T50RP gets very close to the LCD2, it was 80% of its sound quality at Christmas, if I remember correctly, and nowadays they must have reached at least 85%.