chitzk0i
Explorer
Yeah, the 'easiest way' without limiting yourself to one kind of magic sword is to multi class into Swordmage, or even Assassin or Monk. This gives you proficiency with their implements which you can (now) use with any implement power you know.
Monk and Assassin Implements are 'weapons with which they are proficient'.
Swordmage Implements are 'any light or heavy military blade'
As part of the implement errata, the assassin and monk multiclass feats stopped granting access to every weapon as an implement. Those feats now simply grant proficiency with the ki focus.
[MENTION=30760]Zephrin the Lost[/MENTION]: Multiclass into swordmage or look for a weapon like Bradaman's weapon or Crusader's weapon.