Anything can be done but I suspect the biggest question would be why. It wont be a cheap option. You could run either one for less than trying to join together both.
As a project its interesting but you may just end up with something that drives or looks crap.
Well it would be a project, last years was a Toyota RV6, year before was a customised Harley 1200 Sportster, I try to complete one per year in retirement, as I say the series vehicles, one or both are available to me very cheaply but are mechanically a long way from usable, plus I do not want drums and cart spings, the Disco runs and drives great its just got a "see through" body, I like the idea of a series with aluminium body, soft top, no frills interior, a lay down windscreen and spartan accessories, I don't think it would look "crap", at the least it should look like a series on steroids, simple but functional, I am not a purist.
I enjoy driving my current, (good), Disco 1 and think it would be good if possible to have this years project a hybrid, modernised, Land Rover series, if it is at all possible, thus the question, "has it been done before", anyone?