I've read several articles that specifically say the current CDMA equipment can be made to access both data and voice. Most seem to point back to one press release, so I won't waste space with multiple links:
From:
CDG : News & Events : CDG Press Releases
The greater question is whether this is something that is changed at the tower, the devices or both and if it then requires changes on the devices, are those changes in hardware and/or firmware. From a quick search for more information, the implication is that it would require a hardware change. So, I wouldn't get your hopes up too high.
Further, the question becomes what the associated cost taken in conjunction with the roll out of LTE. Perhaps it's pointless to to push out SVDO and instead just go with LTE. On the otherhand, perhaps SVDO is cheap enough to help stretch the legs of the existing CDMA network in places where an LTE investment doesn't yet make sense as it seems the complimentary enhancement could allow for more spectrum to be used for data.
Who knows...