Not sure of the correlation
The two are not necesarily related. You can develop webOS apps without a phone, for the most part. Their development kit contains a full emulator that behaves just like the phone.
Also, in the States the Pre and Pixi are now available on both Sprint and Verizon (later this month), though they may stay on one carrier per country in Europe.
It would be cool if they released an unlocked developer phone though.