Doppleganger that can do more?

[Dramorake]

Is there any classes that could make a doppelganger turn into more things then just the humanoid type?

[Kazudo]

Not classes, unfortunately. If you can gain access to the correct spell or spell-like ability, then you can get the Doppelganger's ability sort of impressed upon any type. For example, the mountebank prestige class actually grants Alter Egos which are similar in nature, however they're based on the creature's base type. Warforged who go Mountebank, for example, can Alter Ego into a specific Animated Object of their choice as long as it fits the other parameters.

[Dramorake]

Well, I figured I could get it done with the right spells and stuff if I searched hard enough, I just really liked doppelganger and wanted to see if I could enhance the shape changing somehow, if I were to get the spells for it there would be no point in sta t ing a doppleganger

[Giddonihah]

Being a Doppelganger means you can qualify for the Shapeshifter Prestige. (http://dndtools.eu/classes/shapeshifter/) Being a Shapeshifter gives you Wildshape which will then qualify you for Master of Many Forms (http://dndtools.eu/classes/master-of-many-forms/)or the different Wild shape feats.

Feats such as:
Dragon Wildshape
Aberration Wild Shape (requires abberation blood and wildshape.)
Exalted Wildshape
Frozen Wildshape

Not shapeshifting persay, but 2 lvls of Chameleon gets you a floating bonus feat, you can use the floating bonus feat with Assume Supernatural Ability to choose a new creature to perfectly emulate each day, to a degree that you can actually blend in.

edit: Note that Shapeshifter has been updated to 3.5, and it has the fix that the max HD you can wildshape into is set to your character lvl, not your class lvl. This means it stacks with your Doppelganger HD. Also its best to go only 1 lvl Shapeshifter before entering into Master of Many Forms.

[(Un)Inspired]

The wizard class lets doppelgangers turn into things other than humanoids. They get a spellcasting class feature that grants them access to spells like shapechange and polymorph that let them assume loads of different types.

I think the class can be found in the PHB.