Dear Dertonarm: It depends of what we all really want it: a serious cartridge shootout or a shootout just for fun.
Just for fun any of the commercial units you name it can be use.
I take the Pedrillo good idea of the shootout to more than a " simple " shootout make something where all of us can " learn " on the why's of the contest results, trade offs and how we can take advantage on those learning exercise and due that we meet in a serious way then could be a good opportunity to begin/build that International AHE Audiophile Association and leave that meeting with something real where all of us can participate and be actors in the near future and not only spectators on how the AHEE must grow up.
Well only my thoughts, unfortunately I can't be there in May but like I say we can have a meeting/tour again by October that you already posted will be at 2-3 hours from Mexico city.
In principle other that the " tour " I would like that all of us can have the opportunity to be in " touch " with three MM/MI cartridges: the Technics one, the Azden YM-P50VL and the AKG P-100 LE and in the other side the Olympos, A-90 and other two top LOMC cartridges that any one of you can suggest.
With this in mind and especially with the MM/MI's my target/priority is that these cartridge can be " serve " in even overall conditions as the LOMC ones.
Anyway, here IMHO is not the place to discuss and to achieve the whole factors/needs/touring and the like of the meeting.
Like you there I'm focus here.
This kind of meetings can be make by the desire of the " community " my email ( as yours ) is open for any kind of suggestion about and for the people can say/decide: I will be there, count with me for May or October.
Regards and enjoy the music,
Raul.