If you want to prevent the quests from letting you advance beyond a certain point (say, 60) then I believe the trunk version will use whatever is set in settings.lua. It works by disabling the genkai quests, so anything that isn't a multiple of 5 won't work.
If you want to allow players to go beyond 75, you would have to modify the existing genkai quests, since the L80+ genkais are not scripted. Alternatively, you could find the text and NPC data, and script the quests.
If you want to remove genkais entirely, there's multiple ways to do it.
- Change /sql/char_jobs.sql so that the default value for 'genkai' is whatever you'd like. It's 50 in the trunk.
- Change /scripts/globals/server.lua so that the CharCreate function includes the following, where ## is the level cap you want:
- An NPC that uses the same script function as part of its behavior.
Note that the first two will only impact new characters. Existing characters would have to be edited. The third method requires new players to know about the unusual behavior, and since dialog isn't customizable, it's not very clear that it happened. You can throw in a "player:messageSpecial(textid);", but you'll need to hunt down the appropriate textid for that zone to display the new level cap.
Also note that all three methods may have conflicts with the trunk, so you'll have to keep that in mind every time you update your server.
Personally, I'd go the SQL route. Least likely to be a problem, until/unless Geo and Rune Fencer are added, and even then it probably won't conflict.
And finally, note that L75+ content is not a priority, and probably won't work properly.
I think some of the gear is also completely missing item_mods, including defense.