Not a prediction, it's more like...
Speculation.
It's fun to speculate about stuff like this. So, don't jump on me when I say...
And if I had any say in what the next Macbook Pros will be like, it would look like the MB Air but bigger! I'd say make it come in 17", razor thin profile top case, liquid metal alloy, satin finish. With matte edge to edge screen for us photographers and designers. The gentle taper of the bottom case would be tall enough to house 2 or 4 light peak ports, 1 or 2 on both sides. (Ok, maybe just 2) The latest mobile version Intel processor and latest GPU. Small/micro form factor SSDs and memory. No optical drive, you'll have to buy an extnl SuperDrive. The body would be a unibody incarnation with carbon fiber to keep the frame stiff and light. Battery would be thin Lithium Ion Polymer cells arranged to fit the entire front half of the bottom case to give 10hrs of battery power during moderate load use. Target weight: <6lbs.
Ok, ok, I know there are some engineering hurdles to jump over but it would seem that most are actually doable. Design-wise, you can have the body taper from 1" back to .25" front. Stiffness in the body and top case can be reinforced with carbon fiber to keep weight down. Battery life and heat management would depend on the speed of the processor and supporting chips...I don't think going quad core and anything over 3GHz would be practical unless energy consumption and heat can be minimized to acceptable Apple guidelines. The battery would have to be formed as a wedge shape with multiple cells to fit the tight front panel.
I know, my musings are just fantasy but it's great to verbalize them. What would you add/or dismiss?