Wow! Talk about a lot of interesting opinions! Sorry I am not a guy weighing in but here are my two cents:
I think it is important first of all to always remember that to God all of His children are beautiful and unique be they extroverts or introverts.
I try and use the temperament test as a guideline rather than the rule, it can help you but it can also hinder your search depending on how letter of the law you are about adhere to what temperaments work together. God knows who you are looking for it is important not to try and outrun His timing.
Also sometimes, you just have to keep trying. My older brother (he is sanguine/choleric) dated about 10 different women before he met his wife. He knows a lot of good catholic women. :) Keep looking you will get there.
Basic identifying question when looking for melancholics? Do people drain your energy or are you energized by being around them often? I love going to parties, meeting new people, hanging out with friends, etc. but I tend to reach a certain point when I need peace and quiet to recharge my batteries.
With regards to sanguines or choleric thinking we melancholics are extinct know this: it can be hard for them to understand just how much quiet time we need in our day to day lives. It is really good for us to get out and be with other people, to volunteer, to intereact with other people but sometimes it can be difficult to work up the energy and motivation - we are very creative about keeping ourselves amused and engaged be it with music, books, studying, work etc.
On a slightly different note Naomi, I really enjoyed reading your posts. My older sister went to school with some of the band members of Scythian.
Sorry this is so long!