Traders not wanting to sell you something makes no sense. Maybe trying to rip you off is fine, but not selling at all like a secret stash? Ludacris. (Wow, Google correct...)
snipped out the bit i actively dislike. the idea would just make traders into storage that you need to trade with to get your stuff back.
ANY complex creation, like guns, should give you a low base chance for success... And books increase that chance. More books, more chance. This sounds doable in a17 if I'm understanding the buff system correctly.
So, books can be used, but "spent" once read. So a set of say 7 books would net you 70% success. Found another book 1? Oh well, keep looking.
...we have the increased block and item id counts, let's not waste them.