Howe will probably be pretty comparable in price to PSC, but probably a little more expensive. But the nice thing is it works. And as long as you set it up just like they tell you, you will never have any problems with it.
If you are looking into moving your steering box, I know that TnT makes a pretty cool kit to do that. Basically you cut out your front crossmember and put their frame extension and new crossmember in. The new frame part clocks the box flat, effectively allowing you to squeeze 3 to 4" of stretch out of the front end.
The alien tank will allow you to stretch the rear end something like 9 inches. You would have to comp cut your Jeep. Depending on what size tire you run, 7" is about as far as you can go before you need to start cutting away the back of the Jeep. I personally like the look of a Jeep that is not a comp cut much better. I totally understand wanting to keep the back seat. I'm planning on doing the same thing. It is way more fun to have more people with you. And it is nice to have a halfway decent amount of cargo space if needed when you take the seat out.
You can probably count on it being $1500 + to make your axle into a true 1 ton axle. I'm not sure what exactly Currie does with an axle like yours, but you will probably have to get new outer shafts at the minimum, Reid knuckles are $250 each multiplied by 4. that is a grand right there. Then you have to source all the parts outside of the knuckle. I would assume you want to keep with the 5 lug theme? If you have 5 on 4.5 currently you will definitely have to get new wheels. A 5.5 inch bolt circle is the minimum to fit a one ton set up. By moving to a 5 on 5.5 pattern you could easily adapt your rear to match with some Spidertrax spacers or the like though (This would bring your width out closer to the front as well that will most likely gain several inches in width). Anyway, back to the brakes. I'm not exactly sure where you can get them, but I know you can get caliper brackets that will bolt up to a chevy knuckle that will work with 1/2 ton calipers and rotors. Going this route will make it easier to keep it a 5 lug because (I'm pretty sure anyway) a late 80s bronco's rotors can be used in conjunction with an 80's chev half ton caliper set up. I'll see if I can find some time to research that a little better for you. (Finals start Friday and I'm not done til Wednesday).