Summon Nature's Ally

[lux_aeterna]

I'm sure that there are more creatures available to be summoned than the ones mentioned in the php.

Has anyone made a list of the creatures that can be summoned via these spells?
Also, do the rules allow you to customize the animals you summon (i.e. give lower level versions more hit dice and summon as a higher level spell)?

I've done a bit of googling and I can't seem to find anything.

[ocato]

Here is the druid handbook, I think it has some lists of summonable allies from other books and the 'best' allies to pick. Also covers feats, spells, forms, etc. Enjoy.