I found a website that posted a script to see what your potentially mogged weapon would look like with your enchant (it links wonky on my blog, you can still copy it accurately though):
ITEMIDCHANGEMEPLEASE should be the item id number for your potential weapon (listed on WoWHead or the MogIt addon).
ENCHANTIDCHANGEMEPLEASE should be the weapon enchant item id number (listed on WoWHead).
Technically you could change the bracket that says [Your Item] to say whatever you want, it's just a placeholder.
Here's what mine looked like. I wanted to test power torrent on the dagger off Alysrazor.
/script DEFAULT_CHAT_FRAME:AddMessage("\124cffa335ee\124Hitem:28770:4097:0:0:0:0:0:0:0\124h[Your Item]\124h\124r");
I made a macro so I could change out item id's at a whim, click on it, then try on the item link it creates in game.
Here are the item ID's for some major enchants:
Power Torrent: 4097
Mighty Agility: 4227
Thanks to Transrogerification's Site!