I figured that I could pool my questions into one thread, and the members of the community could help one another out with various questions they might have about the game.
 
In any case, I'd take the first shot with a few questions. 
 
-I'm at level 37, and I beat the penultimate dungeon (Gittingham Empire), but I'm having trouble with the final dungeon. Apart from the metal slime family (I have trouble with those guys), is there an easy way to level-grind?
 
-Speaking of that, is there an easy way to find and kill members of the metal slime family?
 
-Where does one find Corundum?
 
-In the sidequest with the wand teacher, which monster has his wand in the Tywill cave?
 
-Where is the belly-dancing teacher of the Illugazar (sp?) Plains?
 
I don't mean to come off as a ninny n00b here (I probably do, regardless) but I would appreciate the help, and would love to answer some other questions that other members have.

I can answer one of these, since metal slimes can only be hurt with physical attacks, the best strategy is to hit them as many times as you can before they get a chance to escape. In other words, speed up your party so that each turn everyone can try to get a smack in before he/they take their turn.

> is there an easy way to level-grind?  
Well I went to The Bowhole, level 3. East of Wormwood. You can run around and find liquid metal slimes that give each member around 10k xp. 40+ should be fair to challenge the next dungeon imo.
 
 >In the sidequest with the wand teacher, which monster has his wand in the Tywill cave?
I found it randomly. I think you just fight a lot of enemies as deep as you can go. That's what happened to me.
 
>Where is the belly-dancing teacher of the Illugazar (sp?) Plains?  
It's one of those bouncing  gem bags. You have to fight a random number of them before something happens.
 
> Where does one find Corundum?  
Exit Dourbridge east. Follow the river north, but you have to get on the upper land and as far as you can go north, it should be there by the lake.

For metal slime hunting, you'll want to learn Hatchet Men (Axe) or Thunder Thrust (Spear).  Those will be extremely helpful in quickly killing metal slimes and will be very valuable for post-game grinding especially when you start meeting more than 1 metal slime per encounter or when you face Metal King Slimes that have 20+ HP.  Bowhole is the best place before going to the last dungeon to level grind as there is a specific spot that you can sit and let the enemies spawn until a liquid metal slime shows up. 

So, yeah! Beat the game. @Jiggah, thanks for the tip about Thunder Thrust. Since I got to "Slime Hill," that's been really helping me out. Thanks!
 
Finally got all those materials. Thanks, @BattleShinobi and @SuperfluousMoniker, for the location of corrundum and the map. I also found where Luminary was.
 
But yet another question - Where does one find a Maoi Minstrel?

Moai Minstrels are in the random maps (Grottos).  They tend to be in higher level maps i.e. lvl. 50+ and usually at the lower levels.