I realize it has been said above, but I'd like to add my vote to have something akin to the old armor/shield/weapon crystals. If that's perceived as too much of a rip-off, make them "badges" or "medallions" or whatever. This addresses (partially) the problem of wanting the ability to use several +1 type bonuses (depending on the expected situation) without having to build a (combined) +5 or higher weapon that can't be afforded. Since magical items can be swapped out of body slots, it makes sense to me that magical enhancements can be swapped out of armors/shields/weapons.
To "fully" address the bonus issue, I'd like to see crystals (or badges or whatever) be treated like wands in the sense that ANY enchantment may be placed within a crystal (instead of having specific crystals). Doing so could certainly incur a REASONABLE additional fee (for the flexibility). This could be either a flat fee (my preference - say, for the cost of the crystal) or a SMALL (less than half) percentage modifier.