[starkiller]

Would like a backup LOMC cart for my Benz Ace which is in a SL-1200 MkII.  Has to be under 1k at a used price, preferably ALOT under 

[Wayner]

Grado Sonata Statement1 @ $600......    (0.5mv) LOMC

Wayner

[Sonny]

Ortofon Kontrapunkt A, $425 on ebay

[neobop]

I've read good things about the Ortofon Vivo Blue ($400), and the AT33EV ($400 at J&R).
I haven't heard either, but they might be worth checking out. I'd be hesitant about buying a used MC. There are also counterfeits coming out of China. 
For something inexpensive the ATF3III at $175 (LpGear) is said to be really nice.

http://www.needledoctor.com/Ortofon-Vivo-Blue-Phono-Cartridge?sc=2&category=378

http://www.jr.com/audio-technica/pe/AT_AT33EV/#productTabDetails

http://www.lpgear.com/product/ATF3III.html

If you just want a listenable backup, one of these might do nicely.

Also, the Denon 301MKII seems to be well liked.
http://www.needledoctor.com/Denon-DL-301-Mk-2-Phono-Cartridge_2?sc=2&category=270