What if mages were able to write their own A/B/S scrolls via something similar to the pen skill?

I'm thinking a high failure rate and also a fairly quick item decay - this would prevent writing and hoarding the scrolls. It would also enable other classes (thieves) to steal them, similar to the wands.

Writing these scrolls should be a pain in the ass, mind you, and the effects would vary based upon the mages' level and skill.
Also, various paper/pen types could alter the spells durability and power. This would preserve the need for exploration - you have to find them and test them.