My understanding was that the network needed some sort of minor software upgrade to handle the traffic. That is not the case? Do you know of a source for this (I'm not questioning your credibility, I've just not seen a definitive answer on it).
You might be thinking of 1X Advanced, which does require a software update. That's for increasing the number of voice users per cell.
SVDO is simply the phone talking on two different channels (1X voice and EVDO data) at the same time. The network doesn't care if you do that. Although I'll get you more refs if you wish, even the PDF you posted mentions it:
"The SVDO feature will be supported in new devices, and will work with 1X or 1X Advanced with EV-DO Rev. A or Rev. B. Qualcomm is planning to support the SVDO feature in all of its new EV-DO MSM chipsets."
It surprises me someone hasn't implemented it already then.
Not sure if the chipsets are in wide use yet.