The G4 7448 is not vapourware. However, it's too little too late for Macs obviously. Nonetheless, I thought it would be interesting to peruse the specifications of this chip for ol' times sake.
It turns out the chip isn't a particularly cool chip, even though it is manufactured on a 90 nm process. At 1.7 GHz, it puts out 30 Watts:
In other words, it puts out almost as much heat as both cores combined of a higher clocked Intel Core Duo chip, and each core alone would on average be faster than the G4 1.7 in native applications, even despite the new G4's bump in L2 cache.