The only good portal maps that I have found are: this one, and Portalcraft: Ultimate Saga.
I have yet to even get my hands on a copy of Portalcraft: Ultimate Saga, but it looks amazing, and is also in the process of being updated to support 1.4.X+ !
I would like to remind you that this version of PortalCraft only works up to MC 1.2.5!
If you try to play the map on anything after 1.2.5 (1.3.2, 1.4.2, 1.4.5) the map DOES NOT WORK! There are blocks missing that you need, energy ball generators missing, the portalgun itself is missing, and the turrets do not attack.
I do, however, have all of the necessary files for PortalCraft if anyone wants to play with it. I also have a full MC125 w/ PortalCraft backup. I do not have permission from the author to post or share, so, that I will not do.
We are all eagerly awaiting new versions of these maps, because they are AMAZING! Everyone has lives, work, school .. etc. Patience guys !
Guys (creators of the map) I can update the map, and traduce it to other idioms like spanish :D, or italian, portuguese... I only need your permission to update it! (Sorry for my bad english, I'm spanish)