eWeek today reports analysts' predictions which state the famed IBM PowerPC 970MP dual core G5 may make an appearance at Steve Jobs' WWDC keynote on Monday.
This prediction seems quite feasible, and in fact I was predicting the same thing myself, especially given that we already have IBM confirmation that the 970MP exists:
If the 970MP was to debut in a Power Mac at WWDC, it would likely only debut in a quad (dual dual core) machine, since the Power Macs were only recently updated. Such a machine would probably sport PCIe, and could be priced at about $3999. A reasonable debut clock speed would be at the very least 2.3 GHz, although higher speeds (such as 2.5 GHz) seem plausible. The other possibility for a machine that would utilize dual core chips is the Xserve, which is due for an update soon.
The eWeek analysts are less sure about a PowerBook G5, but I suspect that Apple would much prefer to ship a new form factor G5 PowerBook as soon as possible. While the coming G4 7448 (especially with its 1 MB L2) is a capable replacement for today's G4 7447A for most usage, its floating point performance is still very problematic, at least when compared to the G5 (and current x86 chips).
The main issue with putting a G5 in the PowerBook is the thermal output of the chip. Ideally such a chip should be less than 30 Watts maximum in a laptop, although slightly higher wattage chips could still be used. I suspect a 30ish Watt chip is feasible right now at speeds up to 1.8 GHz. Based on this, I would predict a PowerBook G5 line this year with speeds of 1.6 to 1.8 GHz (although not necessarily at WWDC). To replace my aging PowerBook Titanium G4 1 GHz, my PowerBook of choice would have these specifications:
13.3" 1152x768 widescreen (104 ppi)
1.6 GHz G5 (with 512 KB L2, although 1 MB would be preferred)
512 MB PC3200 RAM built-in, expandable to 2.5 GB
PCIe, with Radeon X300 128 MB
Dual-layer 8X SuperDrive
Bluetooth 2.0 & Airport Extreme
80 GB 5400 rpm drive
A line with this unit at the bottom end would sell extremely well. We'll know soon enough however, with WWDC now only 3 days away.