Btw, I won't be getting my Inc HD till around Christmas with the way things look, so I would like to throw this out there for something to try.
And yes, I know this is early, but why not go ahead and say it.
I could see us easily getting temp root by using Visionary for the Desire HD. This roots the G2 and DHD upon boot, so it is LIKE having perm root. Can even have it run certain scripts at boot to change certain build.prop settings and such.
If this phones are as similar as we think, it should work just fine.
And, once the kernel source is released, we could just as easily have overclocking and undervolting too. I've seen DHD overclocking to 1.46Ghz and undervolting of over 100mV.
Just something to chew on for those of your planning on getting this.