Waves UltraPitch is currently on sale for $29.  Haven't tried it but looks formants can be adjusted.  
 
http://www.waves.com/plugins/ultrapitch

Since my newest computer has loads of space, I decided to install every version of Sonar I own (the rights to use) so that I would have access to all the plugins I paid for if ever I should need or want to use them.... but mostly so they would all be there when I open very old projects that contain them.
 
Since V-Vocal is the only Sonar plugin that has formanting capability, it remains installed and on hand for that purpose.
 
I mainly use it to bring vocals "back" to reality after changing the pitch, not to alter them. It works quite well for that.

Audacity can do some interesting things..
 

The forments aren't changed in this though, it's just slowed, and so a lower pitch. Changing the formants would do the same without slowing the track or changing the pitch. You can do the same in Sonar
 
The slowed record version that sparked that has the same effect

 
 

Kamikaze
The forments aren't changed in this though, it's just slowed, and so a lower pitch. Changing the formants would do the same without slowing the track or changing the pitch. You can do the same in Sonar
 
The slowed record version that sparked that has the same effect

 
 

Yes, I am aware that this is just a standard speed change simulating 45rpm played at 33.3rpm. The OP was asking about pitch shifters - I was simply making the point that Audacity is a useful tool that can do this as well as many other things.

While we are at it, Sonar Platinum should have Formant Scaling, but this option is grayed out. Any reasonable explanation why it doesn't work, or it's a bug?
 

 
 

Soundwise
While we are at it, Sonar Platinum should have Formant Scaling, but this option is grayed out. Any reasonable explanation why it doesn't work, or it's a bug?
 

 
 

Formant Scaling is only available when the chosen algorithm supports it.  MPEX algorithms that were available in SONAR prior to version X1 supported formant scaling.  The Radius algorithms do not support formant scaling.
 
Hope this helps,
-- Ron

For all I know MPEX may still be available, I do not install 32bit SONAR. MPEX was never ported to 64bit.

SquireBum

Soundwise
While we are at it, Sonar Platinum should have Formant Scaling, but this option is grayed out. Any reasonable explanation why it doesn't work, or it's a bug?
 

 
 

Formant Scaling is only available when the chosen algorithm supports it.  MPEX algorithms that were available in SONAR prior to version X1 supported formant scaling.  The Radius algorithms do not support formant scaling.
 
Hope this helps,
-- Ron

Thanks for this info! I might be wrong, but official iZotope docs say that Radius does support Formant correction.
 
http://help.izotope.com/docs/rx/pages/reference_timestrethpitchshift.htm
 
http://help.izotope.com/docs/rx5/Time_and_Pitch.html
 
http://downloads.izotope.com/docs/rx6/54-time-and-pitch/index.html
 

I pitch-shift male and female vocals in Melodyne quite frequently and they sound fine without any formant correction.  That said, I limit transpositions to a whole tone in most cases.