I don't know what's a base speed but Bobcat is sold up to 1.7GHz (E2-1800), +10% mechanically gives 1.87GHz, maybe 1866MHz if we like round numbers.
Some new "info",
http://fudzilla.com/home/item/29953-kabini-to-be-10-percent-faster-than-28nm-bobcat
Jeff Rupley, Jaguar engineer is saying that Kabini is expected to clock 10% higher than Wichita was (cancelled 28nm bobcat). So I'm starting to think 2GHz is quite realistic, if not higher.
There is the new introduction of the X series with Kabini, which bring a 25w TDP. That's almost a 50% increase in TDP over the highest 17w bobcat part. So we have a process shrink, 50% higher TPD headroom, but twice as many cores, twice as much cache, wider vector units and more transistors per core all round. The shrink should come close to covering the fact the chip has more than twice the transistor count. With the 50% higher TDP on top of that I think 2.0-2.4GHz is probably likely, and these are the parts that are more likely to end up in consoles.
The only wild card is using more than one Jaguar CU. Are we talking 8 cores, 12 cores or 16 cores. I think at 4 we are pretty much guaranteed a clock speed over 2GHz, at 8+, maybe not as likely.
Now for some speculation based off known TDP's; how about this APU:
12 Jaguar cores w/ 6MB L2 cache @ 2GHz (75w), 1536SP custom 88xx series GPU at 1GHz (110w), 185w total for APU, die size 350mm^2+
Memory and misc could add 50w on top of that for a total system TDP of 235w.
Such a system is about as good as I'm expecting, granted using stacked memory with a capacity of 8GB+ and speed of 200GB/s+ would ultimately be the icing on the cake if it doesn't blow out the TDP, cost, or launch timing of the system.