Along with Get-Lo I long for a day when humans shake off religion and recognise it as folklore. As for Elvis being a religion, I'd say he offers the same service as a religion, he pushes the same buttons for a devoted fan. I'd also say the people lining up on the candleight vigil are exhibiting a form of worship and ritual.
And I don't mind at all, if that's their thing. I don't see it as an act of blasphemy to a sky god because I don't think there is a sky god.
Elvis as a religion? Yea, why not. Where's the harm? I reckon it would be a safer religion than most.