This 44 inch tires idea actually came up just yesterday, whilst on a visit to Tarnol. As is usually the case, Nikki Ustad and I had gone there for something else, and ended up looking into something completely different.
The tires which we liked the most were a beautiful set of 13.00R20 ones made by Bridgestone. Fresh stock (late 2012), too!
Now, for the sake of comparison, the Phantom currently wears Super Swampers in 15-42-15 size. This equates to 385/85/15 in metric terms. In layman's terms, that means a width of 15 inches, height of 42 inches, and a rim size of 15 inches. Pretty formidable!
The 13.00R20 size equates to 365/85/20 in metric terms. In simple explanation, that means a width of 14.4 inches (a little thinner), a height of 44.4 inches (much taller), and a rim size of 20 inches (much larger). We placed the tires next to the beast, and I have to say...they look awesome.
Theoretically speaking, this should 'lift' the rig by about another inch or so, and make the tires sit a little closer to the wheel arches and fender flares. Of course, the downside to this is that a set of 20 inch wheels would have to be purchased, too. I'm tempted to follow through with this. Just for the sake of bringing the truck into that category of rigs which rides the largest tire size currently available. 44s are the largest 'regular' size of tires currently making the rounds. Even were I to NOT fit these tires yet, I think it'd make a useful purchase, until such time as I run the Super Swampers into a state of lifelessness. Purchasing items when you don't immediately need them, is better than doing so in a rush, when you're pressed for time to keep the rig on road.
Let's see how this 'New Year's present' for the Phantom unfolds.