Finally, and this is something that I did not take into consideration any, is that I am at 7200 ft. Can this altitude have an effect on brewing like it does with baking and cooking?
The altitude issue was raised on an episode of the Sunday Session on the BN about a month ago and nobody knew the answer to it, but it seems unlikely to affect the gravity by 1.008 but I don't actually know. Another variable to consider is the temperature for the sach rest. What was the temperature suppose to be? If it was too hight the wort may not have been as fermentable.
Also consider your yeast pitching. Did you need to make a starter? How old was the yeast? What was the fermentation temperature? What strain if yeast did you use.
Like mtnrockhopper mentioned, what was the OG. An FG of 1.020 would likely be fine in a high gravity wort. There are many variables to consider and taking good notes will help in determining the cause.