Ok so I have been thinking long and hard about this, and i think we should diverge from the runescpe standard.
Pratically speaking, I was thinking in the lines of bridging skills. For example, skilling minigames should give the option to give experience for combat skills, much like the zeal system; the reverse should also be possible, like combat minigames giving skiller experience.
Perhaps even giving every skill a 'task' of sorts, like gather X number logs and get X points for that skill, or bonus exp..., that could be exchanged for equivalents of slayer helmet, maybe lumberjack gear and so on.
I mean, if you are playing in a private server you are going for something different than rs right?