First before I give my suggestions, might I say congrats for choosing Loki? I, also plan to cosplay him though it's been taking my commissioner a while to finish. I shall be cosplaying his "Kid Loki" version from the comics. Now, for suggestions. I say if you can't make it yourself definitely get a commissioner to make it for you. With that, I can only think of one these cosplayers/commissioner and each of their cosplays are different. Sadly not sure how much they charge completely but my fiancee ordered from the first and it cost her about 600 for armor included with the costume.
Her commissioner is: CosplayMandy and she's made two other Lokis that I know of -
*Lopti/Some like it Blue http://th07.deviantart.net/fs71/PRE/...is-d52v5fn.jpg
second commissioner: Aicosu-
third: KidofMischief (on Tumblr)
Sadly don't know how much they charge but you should definitely ask them for a quote for a Loki cosplay.