If you need help with red stone work and command blocks just email me and Ill lend another two hands!
Downtime Update #2
After doing some work on setting up custom villagers, I realised that it's pointless to keep using this trading system.
It would be perfect, exept, due to a very werid bug, villagers that are contained seem to have a chance of despawning whenever the world is loaded, which means that, until the bug is fixed, the "trading systems" will keep on randomly dissapearing, which makes them pretty useless.
I'm not quite sure what I'll do, but I may setup a system using command blocks. This would be more time consuming, more space consuming, and more complex than using villagers, but it won't randomly despawn.