I'm not sure what "overland" is supposed to mean either. Particularly here in the states, I think the more appropriate term would be a "wilderness" Jeep. To me, travel in the wilderness requires many things the most important of which are (1) the ability to self-rescue because of the inability to obtain assistance or reach civilization in less than one day's hike and (2) self-sustenance without the need for re-ration or support (food, water, equipment, etc.) from civilization for the period of time traveled.
Depending on your mode of travel, and the topography of what is to be traveled, the gear you bring to satisfy (1) and (2) above will obviously change. I fail to see how having a flip-top tent on the roof of a Jeep makes it more wilderness capable than another Jeep that has a 4-season tent or bivy sack stored in a bag in the back. Actually, I can think of many reasons why the latter would be a MUCH better way to go than the former. (If your Jeep becomes inoperable in the wilderness, it's pretty hard to carry your flip top tent on your back to use as shelter on your multi-day hike out...oh, and there is that whole weight savings thing.) I also fail to see how a Jeep with 35's and a standard lift is somehow more wilderness capable than a Jeep turning 40's with coilovers. The only argument I could see is if the distance traveled is so great that the relative difference in gas mileage becomes an issue which cannot be planned for through preparation (i.e. bringing extra gas). Here in the states though (particularly the lower 48), that problem seems unlikely.
I guess my point is that "overland" has become more of a cliche for a type of look and less of a definition of capabilities. If your Jeep is built to cover the terrain you plan to cover, and you have the ability to fix it and perform self-rescue, then the rest really comes down to what else you throw in the back and what you have between your ears, not how the Jeep was built. Just my .02.
+1 for Sharkey. I think he nailed it.