Shade used CR+X as a placeholder until we figured out the CR.  Then he went back and put in the specific value at the end (except when he forgot).
		
		
	 
That's OK by me, so I guess I might as well put it in the Working Drafts:
Updating the 
Walking Egg Working Draft and 
Wingless Wonder Working Draft.
How about this for the 
In Faerun text:
In Faerûn
In recent years it has been fashionable for powerful wizards to use 
polymorph any object to transform their rivals into wingless wonders. Such transformed wonders cannot speak or perform precise gestures so are unable to cast spells with verbal or somatic components, so most are stuck in alkada form until they can find someone to break the enchantment upon them.
 
	
		
	
	
		
		
			Given that a typical wingless wonder is SR 23, I'd go for a flat SR 23 in the spell also.
		
		
	 
That's my preferred solution.
Revising...
Wonderform
Transmutation
Level: Sor/Wiz 8
Components: V, S
Casting Time: 1 standard action
Range: Personal
Target: You
Duration: Permanent (D)
This spell functions like 
shapechange, except it enables you to  assume the form of a wingless wonder. You gain all extraordinary and  supernatural abilities of a wingless wonder, including its continuous 
mind blank and spell resistance 23, but you lose your own supernatural abilities.
While in 
wonderform, alignment detection abilities register you as chaotic neutral. Other alignment-dependent effects, such as a 
chaos hammer spell or an 
axiomatic weapon bestowing a negative level on chaotic creatures, will affect you according to your actual alignment.
The 
wonderform  spell ends instantly if you assume the form of another creature but is  otherwise permanent until the spell is broken, you even remain in 
wonderform  should you be killed. Any parts of your body that are cut from you  (i.e. the wingless wonder's tentacles) do not revert to their original  forms.
You can cast spells and use spell-like abilities while in 
wonderform. Material components that melded into your body when you assumed 
wonderform  can be used to cast spells but are otherwise nonfunctional. Wingless  wonders are incapable of meaningful speech, any verbal spell components  you utter sound like high-pitched chittering but still function  normally. You use your tentacles to perform any somatic components a  spell might have.
Other creatures who observe you spellcasting have a -20 penalty on Spellcraft check to identify a spell you cast, due to the 
wonderform's perturbation of the spell's components.
The alien structure of a wingless wonder's brain puts great strain on your mind. At the end of every 24 hours you spend in 
wonderform  you must succeed at a Will save (DC 15 +1 per day after the first) or  take 1d4 Intelligence damage. This damage cannot reduce your  Intelligence to below Int 6 (the average score of a wingless wonder),  but if your Intelligence is reduced to 6 or lower you lost the ability  to dismiss the 
wonderform spell and will remain a wingless wonder permanently unless another effect breaks the 
wonderform spell.
There are tales of spellcasters wandering for decades in the shape of a  wingless wonder before encountering a helpful creature able to use 
break enchantment or 
polymorph to return them to normal.