"And the answer basically is: If the US want him, they need only ask."
Yup. That's the bend over and give everything to the US agreement Blair signed with the US, though it's been relaxed for Asperger's syndrome it would seem. If he wanted to avoid the US he should have let the British send him to Sweden; under the terms of the EAW they cannot send him to the USA and, in any case, we're more cooperative with the USA.
As an aside, Assange (who once said he wanted to live in Sweden) described the Swedish CJS as being of 'banana republic' standards; aside from the faux pas here, they have to comply with the EU standard.