I think it depends on how nice of a paint job you are looking for. Knowing how your blazer looks, I know you go for a really good paint job and in that case yes, ~$5k or more for paint. But some of us don't care to have it look perfect. Some of us just want it to look pretty good from 10ft away and in that case you don't have to spend that much on a paint job (~$2-3K).
And yes, if you are doing a full restoration on anything, $30k better be what you figure. But once again, it depends on what the OP (or any of us that are doing or considering this) really want out of their truck. I want a good looking dependable tow rig. It doesn't need to be perfect, but I just want it to be a clean looking square that gets used. In that case, absolutely you can build one for $10-15k and your time.
To the OP, if I were you I would probably just pick up a rig like the one you are looking at (referencing the Ford) since you are still in the building stage of your other rig. Being someone that has 3 boys that are 4 yrs old and younger, I can appreciate you wanting to not take all your time working on rigs and spend some time with your kids. Luckily for me, my crawler is pretty much built to where I want it other than small misc stuff here and there and if stuff breaks while wheeling. So now I have the itch to build something again and that's why I'm taking this build on. Plus, I am going to try and get my older boys that are almost 5 and 4 yrs old more involved with this build with stuff like cleaning out the interior, ect.