That was a good read, tot - - thanks for sharing. That Radial Dragster might be something worth checking into in regards to enhancing the tones I get using my PODxt.
The author of that article makes mention of the Atomic Reactor tube-based amp in regards to his own live sound, and like any gear offering, I've read reviews both ways. Personally, I haven't tried one, so I can't expound with any comparisons.
Flat-response amps are really a key part of the modeling equation, and there are many different approaches as to the best way to go about it. Myself, I use a Tech 21 Power Engine for amplifying my PODxt tones live, and I've been very happy with the results.
More on that here:
http://www.thefret.net/showpost.php?p=4457&postcount=1
Although I'd consider the T-21 more of a powered extension cabinet than an amplifier, I will say that it "images" the PODxt's amp models very realistically, and is responsive to the various playing styles I employ. Unlike the Atomic, it's solid-state, which some might think pulls away from the character of the Line 6 modeled tones. Actually, I've found this to be the opposite. Totally vanilla (meaning not running anything but the PODxt straight into the T-21), the tones are pretty convincing - and dare I say it . . . tube-like. Being that Line 6 developed the POD's technology tube-less from the ground-up, people sometimes get the wrong idea that these units won't sound good on their own. They do - very good, as a matter of fact. Anyways, the solid-state thing is becoming less and less of an issue with players who use modeling, and I think that there'll be more of these types of gear offerings (meaning solid-state gear to be used in conjunction with modelers) in the future, as they score big in both reliability, and no-fuss maintenance. In the case of the T-21, it was about $250 cheaper than the Atomic.
Now onto the tube / modeling thing: I've recently started using an ART Project Series tube-based pre-amplifier at the first part of my signal chain (from my guitar to the PODxt). From there, I run the ART into my PODxt, and then out through my T-21. What this allows me to do is push the gain stage prior to the signal hitting the PODxt. The 12AX7 tube in the ART imparts that warm, organic sound to the signal, and thus, alleviates the need to use the gain / OD on the the PODxt - which in my opinion sounds a little bit too "digital" on some of the models. I'm still in the process of tweaking a lot of my pre-sets to work with the ART, but so far, the results have been impressive - esp. with the Fender-y / Vox-y stuff.
The Line 6 forums are also a good place to harvest ideas in regards to using modeling tones live, and a link to that site is already posted somewhere on FN.