This could be a PITA, any way you look at it. Consider:
1-unless the laptop has Thunderbolt, I don't think there is any way to do it.
2-With thunderbolt, an external chassis and proper cables can make the physical connection, but there my be no Windows driver that works.
3-Even though I am a PC guy, I am reluctant to recommend any windows laptop(in favor of a properly configured MacBook Pro).
4-why do you feel you need HDX? Modern native rigs are more than capable of serious(IOW, "pro") production in most cases.
5-For me, the only reason to use a laptop is for portability and adding a chassis for the HDX card, plus a Digilink interface seems counter-productive(again, that's only my opinion)
I ran a commercial studio in Nashville for several years with an HDN card in a Windows desktop and did plenty of full-blown productions for commercial release and never felt I was cheated(or that I was cheating clients). Its important to have realistic expectations before you rush out and buy lots of stuff(especially if its because somebody told you that you need that). Food for thought
