Why to fabricate some maybe it holds up, fingers crossed stuff as there is plenty of original spare parts available for not too many €? 
I just bought set of headlights in mint condition( yes, xenon headlights) for 20€/pair.
And your fix is not really a rocketscience to pull off 
Martin
I drive this every day to work and i work overtime each week. I don't have time to do it properly during the week.
I just want a real fast and cheap fix to it.. At the moment it's just held on by the top cap.. And it feels loose and wiggly to the hand.
I thought it would have been just a screw off like all the other cars have.. It's overengineered.. I was thinking about putting an 8ball or something to it but since it requires removing the whole gear lever and replacing it then i'll just let it be.
EDIT:
Okay i searched trough the web and the only way to remove the knob is to destroy it..
I'll probably just pull the leather off and melt a plastic skull or something on top of the metal piece and boom custom gear knob..
Opel just had this poor design to milk money off of it's users and not allow us to customize it.. Typical german engineering.
Never had problems like these on my old mopar.