Thanks for all the feedback on this. Lots to think about on this one. I am going to do some research and test drives in the next few weeks to get a better feel for each different platform. I am leaning towards either the 100 Series or the Tacos right now, but we'll see.
In response to keeping my 4Runner. I think my current car is totally capable, but I also dont think it's a financially sound idea to start taking a saw to a 'new' car with good re-sale value. There are trade offs, but rather than throwing 5-10K at my car to bring the build to where I want, I could quite easily find an existing build or find a stock older vehicle that has depreciated a little more. Then I would be able to have a purpose built rig for about (or less) what my current rig is worth. Granted it would be higher mileage and all that, but I plan to keep this rig for a long time and most likely get a daily driver a few years down the road.
Basically, it boils down to this: IMHO unless $ is not an object, it's better to find an older built vehicle or build on a higher mileage truck than to cut up and build on a 'new' truck. The idea being that once you start heavily modding a truck, it becomes less and less valuable to the general market (ie, dealers and 99% of consumers)...so, why pay more to make your truck worth less.
Obviously you can disagree with me on that and maybe I shouldnt be thinking about resale value but the bottom line is that I can get a lot more truck (granted an older truck) for less money going that route.