I've had the SRM DA Pro Wireless/Edge 705 set-up since June and love it! I just downloaded the most recent update for the 705 and no P norm yet. I hope Garmin spits out an update that includes VI before they do P norm, if either are even possible.

I don't know much about normalized power (don't see the need in triathlon) but I will tell you after buying two quarqs (my bike and my wife's bike) you will not be disappointed. Plus swapping from bike to bike takes only the time to actually switch cranks and move your Garmin, nothing else to set-up. Not as easy as a power-tap, but the increased wheel flexibility is worth it to me.
--Brynn

The Edge 705 does show normalized power; The "average" they show does not include any time not pedaling.

As someone else mentioned; kudos to the folks at Quarq, by the way. I've got two and love 'em. The 705 is okay; not worth the $ over the 305 unless you're using power (my opinion.)

I do wish the 705 would give some sort of a rolling (no pun intended) average of power, however. I'm planning on getting a Qranium just to be able to get things like that.

The Edge is by no means open source but that doesn't mean that it couldn't be hacked. With that being said I highly doubt there is a well-established base of hackers/cyclists out there to do this.