[Threshold]

sounds like it is very well suited to your criterion.

1) Custom Codebase.

2) 30 levels.

3) We don't do remort, but we have specialized sub-classes.

4) We have skills and classes (they are called guilds on Threshold).

5) Not a twink mud. RP is enforced.

6) We do not have 20+ races, but we have 10 that are very developed (some of them are even directly tied into the religion system).

7) We have fishing, digging, tailoring, and a variety of other types of crafting, but no mining and no traditional weapon/armor crafting.

8) Threshold has very detailed, very challenging quests. We also have staff run and developed plot lines.

9) Threshold's world is quite huge and it is 100% original.

10) The player base is very loyal (some have been playing for over 10 years) and the community is excellent. We embrace new members as the vital youth that keeps our community vibrant.

11) Threshold RPG is referred to as "medieval high fantasy."