Well.. the Spanish V sounds pretty much like a B anyways.
As an outsider that never spent enough time in Spain or set foot in Basque country (Pays Vasco
) it's hard for me to suddenly draw lines. But I think it's right that they just stay with Spain. I think the majority of the Basques want to stay with Spain anyhow and it's not like the other regions of Spain are completely Castellano in terms of language or customs anyway. I know the Basques are even MORE different... heck their language doesn't even resemble the Indo-European language thing. The origins unsure etc.
Then again there are so many independence movements in Europe... like in Belgium, also with Catalunya in Spain itself again... also talks of northern Italy going its own way though that's less serious. I've spent time in Belgium and wrote a paper project on it in university but I never got that serious with the Basque situation... so again I can't REALLY say.