I , of course am all for signing a petition.
That being said Dave stated the sitch.
Nokia/MS hasn't released the closed parts in the past...
(even with all the off and on interest and asking that has occurred over the years here)
The one omission in Dave's post is that there was a great deal of collaboration Nokia did back in the day with other parties...
ie. Skype and the like... quite a few other parties are involved in the sitch in regards to opening up maemo.
They would balk at Nokia/MS just releasing their proprietary work.
I'm sure if it happened they would be lining up to sue Nokia/MS.

I think ... at best....very best...
to have the slimmest possibility of the releasing of maemo's closed source aspects...
My best suggestion would be to first get a hold of all the other players who participated .... and ask them to sign off on the release of their grip on their proprietary bits.
After getting all those ducks in a row...
After getting unanimous consent.
THEN head straight to Nokia/MS with those signed documents and the petitions list.
Then Nokia/MS is apt to release the closed source aspects...

But I am positive just walking up to Nokia/MS with a petition signed by 99% of the planet, every head of state, the risen prophets of every faith, the Devil and God themselves ..even... can't make Nokia/MS break binding contracts.

I am not dissing the op , nor his idea ,
But this is just walking down the same old track ...
asking, begging, petitioning or demanding in the same way....
with the same results.....
is just more pissing in the wind ...

Try a different tack.

Go after the players...
If that succeeds
and everyone complies..

then go after the corp.

If they still have the goods..
then there is no reason left for them not to comply..

Then we will get what we need.