For those of you updating to r4, take note that I've renamed PostUpdateIcons to PostUpdateEnchantIcons. The former name was too generic and should have been changed before release. Sorry for the inconvenience.
oUF_WeaponEnchant provides you with icons for your temporary weapon enchants. The code works pretty similar to the normal Auras element, mostly because half of it is the same code. All you need to in your layout is create a self.Enchant frame, set its dimensions and any options you want and you're good to go. You will also need to add oUF_WeaponEnchant to your layout's OptionalDependancies.
More information on how to use this can be found at the top of the Lua file.
A large part of the code was written during a sleepless night, so there is a slight chance of some things not working properly. If you happen to find one, please post a comment here and I'll try to fix it as soon as possible. The same goes for any suggestions you might have.
haste for oUF and the Auras code, on which this is based.
Caellian for the idea and feedback.
* Renamed PostUpdateIcons to PostUpdateEnchantIcons to be more specific.
* Blizzard's TemporaryEnchantFrame is now hidden by default.