Oh, I am getting ideas, I will make something for you, but this one will take a bit longer since I have so much I need to finish before the next AGDG jam, having a Leviathan-tune ready within a month is no problem at all though. Thanks for the offer of help, I will probably take you up on that! I need to make some items soon which I want to affect some variables, basically adding or subtracting from them when you equip/unequip that item. I am guessing this can be done with common events since I seem to recall an item can add "eventing" by using those. If I cant figure it out I will ask you!
Yeah no worries about the time, not really in a hurry here. For your items/equips, if they are just usable items in the db yeah you can add a common event to change some stuff but in the case of equips you will probably need something else, it all depends on what you want to do really.
If what you want is to track a certain equip being equipped or unequipped I would add a passive skill (like the ones you can add through visustella) thats set to Ocassion: never in the skills tab and have a parallel event on the map that checks if said skill is present in the party character with $gameParty.members()[x].hasSkill(y) == true and so turn switch Z on so that now it starts checking for $gameParty.members()[x].hasSkill(y) == false and do your logic for each case. The parallel event should have a wait time set (10-15) so that it doesn't lag the game.