Yes, an animal can inherit 2 copies of the pastel gene to make a super pastel (sometimes referred to as an Opal). Pastel is a co-dominant gene. Pinstripe is a dominant gene. In this case, dominant refers to the fact that animals either can not inherit two copies of the gene, OR animals that do inherit two copies of the gene do not look any different than those with a single copy.
pastel: http://www.vmsherp.com/ImagePages/Balls/Pastel.htm
super pastel:http://www.vmsherp.com/ImagePages/Balls/SuperPastel.htm
** i have no affiliation with VMSherp, they were just on top on the google search.
Any morph can theoretically also have two copies of the pastel gene, as far as i know there is no other morph that shares an allele with it. So, a bumble bee is a pastel spider, a killer bee is a super pastel spider.