So if you got the ThinkPad X1 and want to get multiple external LCD support (i.e. more 2), then this is how you suppose to approach this.
If you don’t need the internal LCD to be on, then you can use the HDMI and mini Displayport.
1. The HDMI is capable of supporting 1 LCD up to 1920×1200 @ 60 Hz.
2. mini Displayport is capable of driving one LCD up to 2560×1600 @ 60 Hz. But:
-If you have two exact same LCD up to 1920×1200 with Displayport input, then
you can drive 2 of these LCDs with one of the Lenovo Displayport to 2 x Displayport splitter.
-While you can still use the LCD with DVI in ports, you must use active displayport to single link DVI converter.
3. You have a USB 3.0 port, so you can get a ThinkPad USB 3.0 dock, which supports two external LCD at the resolution of 1920×1200 @ 60 Hz.
So this basically gives you up to 5 external LCD support from the ThinkPad X1. I got to up to 4, have a look at the picture.