the utsusemi trick works, but as ghost said you need to either get cheap ores or necklaces. I did this with my mule a while back when ores were only 400-600 on ramuh. now they are 800-2000 depending oh who or where you get them from (bazaars right outside AH is usually cheapest)

Back then I spent around 200k to get the fame and I had a friend help me get the keys. Was a little easier because this mule was my first character ever but only 18thf/1war (yes just got subjob quest when i made my current char lol) But anyways I made almost 3x's that in profit selling the scrolls and stuff from norg quest for a little work everytime i was bored lol. Now if I ever want to play nin on my current character, all I have to do is the quests again to get the scrolls ^^
The easiest way I would suggest to do norg fame for a mule, would be when you see cheap ores with your main character buy them and send them to your mule. May take a while but if you are not hurting for gil this would be the cheapest way to do this other than trying to mine them all lol .. that could be quite upsetting

Eventually, you should have enough ^^