Sager (Sagernotebook.com) also makes very solid machines AND they have some seriously high end desktop replacements:
This guy can get equipped with a GTX 770M (Consider what apps you run and if you need the Quadro card for full support) - as well as the 6 core extreme edition CPU and a SSD + 32 gigs of ram for under $3500 and that’s a beast if you’re just looking for computing power.
With that said, it’s 12 freaking pounds without the power brick (which is probably 3-4lbs for a machine that big). Expect to get either really strong shoulders or a hernia if you want something that is actually transportable for long distances. You certainly wouldn’t want to make an hour long commute with that thing.