For instance bloody and burning skeletons.
Not really, bloody and burning skeletons are not templates, they're variants.
But if you have the ability to apply two (different, I suppose) templates, and they don't explicitly prohibit the application of other templates, then you should be able to apply more than one.
pg. 54 of Pathfinder Chronicles: Classic Horrors Revisited has additional varients and information of combining varient types.
And if you look at the last paragraph on 251 of Pathfinder: Bestiary 1 under Variant Skeletons "Except as noted, these variations
can be stacked with one another—it’s possible to have a
bloody burning skeletal champion."
In the Bestiary 1, I see no mention on combining zombie variants but the Classic Horrors Revisited does include combining multiple varients for skeletons and zombies, not all variant types can be combined though.
For anyone using Skeletal Champions or Zombie Lords in their games, Classic Horrors Revisited does include variants for them as well.
^^ Awesome, SC, much better answer than mine :D
I love learning new stuff.
The following thread has some additional information for some of the variants
Not additional templates but for those looking for alternate uses for the Create Undead and Create Greater Undead spells, Undead Revisited on page 3 includes a chart for animating additional types on undead