The other night I had beguile cast on me. Card reads that you cast through the target wizard as if you were in that square. He then cast a spell on me, killing me. I can see both side's of the argument, guess I just want a settlement of the issue, can you attack the beguiled target with a Los spell.

Being in the same square implies LoS (a wizard always has LoS on the square he is in)

The counter argument is the target of beguile is actually casting the spell, so do can you shoot yourself