You know, this reminds me. A year or so ago, I was playing a Tiefling Mage in Dawnforge, and I built him around the concept of being a summoner who was forcibly bonded to the dark form of magic (he wanted the light form, even though he was lawful evil). He hated Tieflings, and hated fiends.
So, he focused his summoning around Pseudonatural creatures. I used the template, and made up my own summoning lists (a la Unearthed Arcana). My summoning lists were filled with pseudonatural dogs, apes, griffons, and the like. It also had aberrations (like Grell, although we had to take it off the list when it WIPED OUT two encounters in a row).
Long story short, the pseudonatural template offered much more "bang for the buck" as opposed to the typical "celestial" templates found on normal summoning lists. Me and the GM had to do a lot of altering to make my concept work, while still being balanced.
Were I the GM in the game, I would probably bar this form of spell-use. Nice thinking, though.