Blakely waivers - Jury Trial Right and Burden of Proof

Every Blakely waiver I have taken a look at provides for a waiver of defendant's right to have a jury determine sentencing factors/elements beyond a reasonable doubt, and to have the sentencing court make a determination using the preponderance of the evidence standard. One could make the argument that it is one thing to allow the Court to make the determinations, but quite another to let the Court make such determinations using a lower burden of proof. Has anyone found a government attorney and/or a judge willing to have the enhancing factors found by the court using a beyond a reasonable doubt standard? What about findings that lower the range of punishment, can they be found by a preponderance while sentencing enhancing factors must be found beyond a reasonable doubt? And what if at trial the government wanted the jury to pass upon, say, a leadership or managerial role in the offense; should that be allowed to be submitted without also including all the alternative mitigating or neutral role adjustments? And do mitigating role adjustments have to be found by a preponderance or beyond a reasonable doubt?