Guys, this is the most helpful information that I have to offer, I think. It may be a bit long, but I'm hoping it may help break up some of the routine of solo play.

I have been tormented with this same dilema during many hours of solo play in this game. Once I hit lvl30 with my RDM, I instantly began unlocking advanced jobs and mission/quests for game. After making some quick advances thru this period (Especially thanks to our good friend Sam's help along the way), I instantly got into NM hunting to break up the routine of trying to farm items. I found that on days I could spend the time to log points thru E.Ronfaure that I had recorded on my map during my trips, and could cover the area quickly. I was focused on my woodworking skills during this time also, which meant I never needed to buy supplies. I found that if I kept lvln up my low lvl jobs while farming Ronfaure, I stacked crystals easily. I would chain (EP)bats in Ronp. Tomb with no problem.

How does this help you ask? 1)(EP) still yielded Wind crystals. These sell for about 1.5k or up. I never had to purchase crystals while working on my woodworking skills, since I farmed my own. See where I'm going with this...free wood, free crystals=free crafting!!
2)Bat drop bat wings/bat fangs/vials of fiend's blood. They were stacked easily and also sell quite nicely in the Auction House.
3)The easiest experience you'll ever get in this game. Sure you're only getting 20-30experience points per battle, but you only need 2k to level up!! Chain 5 bats, that's at least 100exp.
This made those weak low levels much more enjoyable, and added to my wealth by doing it.

So what does this have to do with NM hunting?
I read up on surrounding areas and the different creatures contained in each region, reseaching information on all of the NMs in the area. I found that I ran across several areas that contained lower level monsters, dropped decent items, and that were rarely populated. None of these would yield a cash-in of 300k, but being able to get multiple drops with little or NO competition at all...increasing my chances of getting the rare drop. I gained 3 rare items, each selling for 25k,within 2-3 days. I would fight low level monsters (ex. Bees, Toadstools, Bats, etc) to pass the time and would quickly gain several stacks of items for sell. So within just a short amount of time, I could amass gil steadyily. I remind you...my highest level job that I have currently is 31. So a few of the NMs I fought made for interesting battles, while others were cakewalks. So at higher levels, you are capable of taking down tougher NMs (even if not as famous as Lizzy) that bring in less gil, but can be more productive. Rare drops, stacks of items, and sometimes cheap crystals can at least make you feel that you're time isn't being as wasted.

This is just my experiences in FFXI, and are definitly not the "right" way. I was looking for a way to make farming a little more entertaining....and it has worked for me. Good luck and maybe this will help in a way.