Justubes,
Ahhh...so we actually had the same cartridge in mind :)
I own an original SL-15E (aka S-15E), which according to Ortofon's own spec sheet (which I've uploaded here:- http://i26.photobucket.com/albums/c147/ze_ant/orts15scan.jpg) has an output of 0.04 mV, which I guess takes the prize here...
I actually have the had the same cartridge