It would be interesting, sort of like the locked pipelines in the 9500 and 9700. The only problem is that a good percentage of these GPU's locked pipelines are no good. In theory, the same could be true for the Northwood CPU. If you can actually unlock the HT (sort of like having two pipelines in your CPU) who knows if it actually would be stable. Not to mention the amount of heat that might be generated.
Compare the 1.6a Northwood which has a 16x multiplier (runs >100F idle, >120F load) to the 3.0e which has a 15x multiplier (runs >120F idle, <160F load). Granted the 3.0e has extra instuctions, but it is kind of like having two 1.5a Northwoods in one unit.
This is all theory, and I use these two CPU's 'cause I have both and a 2.5a. The 2.5a can only overclock to about 3GHz, while the 1.6 can safely OC to <2.1GHz. If there is a way to unlock a second "pipeline", the 1.6 could in theory run at 4.2GHz OC. I am basing this on what I know of DDR memory and other parts that have in the last few years been made avaliable with double data handling.
Look at the GPU's out now handling up to 18 pipelines for ATI and 24 for nVidia! Just imagine what a CPU that could handle that would do. Maybe we already have them and don't know it, or they are being use by the military (they always have the good toys first).
It would appear that your mobo is ready for a HT CPU, you just don't have one installed. When I ran FutureMarks benchmarks it said that HT was available but disabled with the 1.6a and the 2.5a. As soon as I put the 3.0e in HT was enabled and it showed two logical processors! Don't feel bad, though, I have a SOYO mobo that I got to go with the 1.6a that was 4x AGP. The North bus chip (845) is the same that is on some mobo's that handle HT, if you can find one that runs 400fsb, or 533fsb. There maybe some in exsitance, but they are not mainstream CPU's.