Ramsey2, You said the key words, "As soon as they are available." Meanwhile, many (I hope VERY many) TPM machines are/have been shipping. These drives will be a good way to break in to the embedded base of IBM/Lenovo, HP, and other ATML/Infineon using OEMs.
So, yes... retrofit (or if you prefer, add-on).
We see it the same way after these are generally available. I can't imagine that secure drives won't saturate to near 100%.
If Wave retains/builds share in this market,... well, it could be huge!
regards