Why Pettigrew's hand?

[Vanessa]

No: HPFGUIDX 28726

There's been some specualtion on the list about the possible reasons 
why Voldie wished to use Harry's blood in his re-incarnation ritual.

As a secondary question, why did he choose Pettigrew as the hand 
donator?  Was it merely an act of convenience (and, of course, to 
allow the Arch Villan to make the usual bad puns; "others would give 
their right hand to perform this duty", etc )?  Or is there some 
special significance?  If abilities travel from Harry's blood to 
Voldie (and possibly vice versa), could Wormtail's angimagi skills 
(and any others he may have...) have been passed to Voldie in this 
transaction?

Is Voldemort already an animagi - he appears to have taken snake 
form, if not actually be able to transform into one...could he now 
have added 'rat' to his repertoire?

Any thoughts?