What type of work are you going to be doing?
Reason I ask is, Intel U-series CPUs are fairly weak. They're great for casual uses, but for more intensive purposes such as a workstation, I'd personally get a laptop with a standard M-series such as the i7-4710MQ.
The problem is that I don't know of any business laptops that aren't using ultrabook CPUs at the moment, so you'll have probably have to use a third-party dock.
If you don't mind using a third-party dock, I would recommend a Clevo.
This Clevo P650SE can be configured to your liking -
http://www.eurocom.com/ec/configure(1,257,0)ec
I'd recommend the following build:
15.6" FHD IPS 1080p
I7-4710HQ
NVIDIA GTX 965M
8GB DDR3
256GB Samsung 850 Pro
Realtek RTL8723BE
(Windows extra)
It comes out to about $1565 after taxes. Of course, this is without any further discounts. I'm sure they would be more than willing to offer you a 10% discount on it + free shipping as they've done for me in the past, bringing it down to around $1410. I'm sure if you're buying multiple notebooks, you'll have even more negotiating power for further discounts or free upgrades.
I think this is way better bang for your buck than the Dell in terms of performance. It's mainly a gaming notebook, but during the time that I had it, there's no reason it couldn't be used as a mobile workstation since it looks exactly like a business notebook (make sure you request the laptop without the Eurocom logos).
EDIT: Oh, I forgot that at least with the 970M configuration, you could plug in three displays natively into the laptop, so you might not need a dock if you don't mind plugging/unplugging cables.