The reason why I think blu ray is possible is this.
The 20gb Pro only gives you about 10gb of space after all the other space gets stolen by the machine etc. You can't easily use this to download movies/series etc, its simply too small. Its cutting the potential revenue sources from media/ online games down and it really needs to be increased if they want to gain market share in this field. So I think they're looking to increase that space to 60gb like a few test units showed up a couple of months ago might indicate.
The problem is once they do that, the Elite SKU is no longer viable. It wouldn't really serve any useful purpose in the lineup. So they have to differentiate it somehow. So the addition of blu ray would do just that.
As far as decoding goes... ATI could work in their decoding chip no sweat into the Xenos gpu so using too much power or being too noisy wouldn't be a problem.
So if A - They want to increase HDD space, they must also B include blu ray drives in the Elite and to do that they have to include a decoding chip in Jasper C.
A - Some small rumors.
B - Consistant rumors KEEP popping up, some originate in Asia where the drives are made.
C - If they were to do B they need to include a decoding chip in a revision which is right about now.
Tease.