codecrumb, I'm not trying to be a jerk or anything, but OMAP4 isn't going to save you tons of power; it's built to increase performance at similar power levels per core. Both the OMAP3 and OMAP4 use the same ARMv7 instruction set so you can throw that out.
From ARM, I think it's probably appropriate to assume substantial power consumption increases for the processor. Scale the processors, and you'll see that Cortex A9 has big efficiency and performance advantage clock for clock, but you're still talking about at least 2x the power consumption.
Cortex A8 < 300mW operation at 2000 MIPS (Dhrystone) @ 1GHz Single
Cortex A9 = 750mW scaled at 7500 MIPS (Dhrystone) @ 1.5GHz Dual
Cortex-A8 Processor - ARM
Cortex-A9 Processor - ARM
If you want to read all the tech speak, scale all the processors out, you should be able to reach my numbers above.
Onto the GPU. According to Anandtech, there's reason to believe the SGX540 was overclocked 25% in the OMAP4440 SoC. That will not help power consumption. Expect more power consumption there, too.
TI Reveals OMAP4440 Specs: Dual 1.5GHz Cortex A9, 25% Faster GPU, HDMI 1.4 3D, 1080p60 - AnandTech :: Your Source for Hardware Analysis and News
I don't see any possible way the OMAP4440 will not require substantially more battery power than the Pre3.
Now that I think that should be settled, do you need an OMAP4440 in a smartphone? Are there any situations in which the mobile apps, the 3.6" display and resolution will require the super powerful OMAP4440? The answer is hell no. Not even tablets need that level of power right now as evidenced by the fact no known tablet will use anything higher than the OMAP4430 (Blackberry Playbook with a 5,300mAh battery, a small 7" screen, and already with battery life complaints to debunk)