Thanks for the reply Roger!
Yeah, I've come to the conclusion the 4D67 won't work for me either. It's so frustrating considering I was able to go the full DIY approach for my USDM 2003 4Runner. In that case, my local auto locksmith wasn't able to do any of the programming and instead referred me to the dealership (which would have been in the range of $200-300 per key). Fortunately, on the 4Runner both the FOB and the transponder were clearly marked as to their frequency/model type, so doing a DIY job was rather easy.
With regards to the Alphard, my local Toyota just took one look at it...laughed...and said "yeah, we don't work on those", and I don't believe the auto locksmith will be any better given our previous encounter...
Still hoping for a reasonable DIY method here!