The thumbnail plugin is not part of DPP, so no reason to think it will happen with a DPP update, which typically happens just to add a new model of DSLR.
HOWEVER
I'm also wondering why Canon is ignoring the 64 bit platform, at least for 64 bit thumbnails. They are the ones with the magic decoding ring for RAW, and should have relleased it 2 years ago.
Of course, there are 3rd party solutions, but with the other relatively excellent 32 bit software supplied with Canon cameras including drivers for 64 bit for most of the newer cameras, its a sore spot for many of us who use 64 bit.