What I'm thinking is that non-casters can create some magic items (mostly stuff like +1 weapons and armor, low-level stuff like that), but they need a proficiency bonus of at least +4, and it takes them a lot longer than it would for a caster. That way you can have your occasional legendarily skilled weaponsmith that can make a handful of "magic swords" or whatever without having him be a caster. I dunno if I'll actually quantify how much longer it takes them, probably something like a 10x time factor or something like that.
Other special magic items I'm thinking sometimes just happen, like flameswords happen when you kill an adult red dragon with a crit or stuff like that. Most of this stuff is gonna be a once in a campaign kinda trip, though.