I've been experimenting with shio & shoyu ramen lately (since I learned that Kitakata was closing, efforts have been redoubled - eep!), and have found that there are some keys to gaining complexity and depth in flavor: 1) browning/roasting the bones first, and 2) using dashi .
Regarding 2 hours vs. 6 hours, I would lean toward 6, as there is more time for the gelatin to ooze its way out of the bones.
Fresh Farms has both pork neck bones and el-cheapo fryers for around $0.79/lb - cheap enough for lots of experimentation!
Stock/base:
1 pkg pork neck bones (~ 4 lbs.)
1 whole fryer chicken (~ 3.5 lbs.)
5-6 garlic cloves, peeled
1 knob ginger (~3.5 oz.), sliced into 0.5" pieces
6 green onion stalks, cleaned and trimmed
Dashi:
6 2"x2" pcs. kombu
1 fistful of bonito flake - stick your hand in the bag, grab, and pull out. That's enough.
salt
1 qt. water
12 qt. Stock pot
3 qt. saucepan
2 sheet pans
To make the stock:
Adjust oven racks to 1/3rd and 2/3rd and preheat to 350. Break down the fryers into their component fryer parts, rub oil on both the pork and chicken, then sprinkle salt the pork bones. Roast at 350°F/180°C for ~ 50 minutes.
Fill the stock pot with ~6 qts. of cold water. Add garlic, ginger and scallion. Bring to boil. By the time you have a rolling boil, it'll be time to pull the bones out of the oven (about 10min or so).
Remove bones from oven and RESERVE THE FAT (adding just a little bit to the finished broth makes a difference). Add pork & chicken bones to boiling water and enough water to cover the bones. This will bring down the water temp. Keep heat on high until it returns to simmer, then drop heat to maintain simmer. You want the water as hot as possible WITHOUT boiling. Skim every 5 min. for the first 15 min., then cover (and drop heat just a bit) and let it sit. My test for "done-ness" is to grab the pork bones with a pair of tongs. If I can crumble the bones, it's done. After 6-7 hours, remove from heat, strain thoroughly (I sandwich a piece of cheesecloth between 2 colanders) to catch any stray pieces of yuck, and you should have 3~4 qts. of stock. Don't worry about defatting the stock - roasting should've rendered most of it, and whatever's left will be minimal.
To make the dashi:
Bring 1 qt. water and kombu to boil in small saucepan. Once boiling, skim off any scum from surface and drop to simmer for 10 minutes. Add bonito, then simmer for another 10 minutes. Strain and reserve. The kombu has glutamic acid, and the bonito, well, it's dried fermented fish, so we're covering the same bases as your shitake and fish sauce.
To prep for ramen:
2 qts. of stock
1 c. of dashi
1/4 tsp. white pepper
3-4 pcs. ginger, sliced to 0.5"
2-3 cloves garlic
salt, to taste
Bring to simmer for 10 min. in a small saucepan, adding seasonings to taste. This is where I adjust to add shoyu to make it shoyu-ramen.
Yahoo Answers has a pretty good
egg noodle recipe that uses AP flour. I've used it with success.
hope that helps.
-s.