Here are some ideas...
Keep vborg free -

- and their code as well and create a vbnet or something to the like with commercial products whom wish to profit from their coding. In this case, for those who wish for free hacks, go to one site, those who wish for "premium" hacks, go to another. That way, everyone is happy - heck, share the same database so that users from one can post and reply on the other and vice versa - no "new accounts." :P
And - give people the right to make their own versions (possibly released under the GNU/GPL?) of the premium hacks - then again, you get what you pay for - and if it's free - well. You also have the option for level of support - those who choose to pay get a better support than those who choose the free version.
I made very little as a coder for phpnuke but I enjoyed making things work - and others happy. It took me the better part of 6 months to figure out how the nuke code worked in order to start with my hacks. I'm on month two with vbulletin code and I'm not doing too bad :P - I'm just now starting to understand how plugins work. But one thing I have noticed is that in one instance where two similar hacks (using plugins were used) one prevented the other from working. That's an issue that could probably be addressed by creating more hooks. But who am I - just a newb LOL!
Edit: Of course, you may want to get permission from whomever if you want to create a knock-off free version