It's not (necessarily) a showstopper.
Just something to be aware of; there was other discussion a while back on this theme, probably in more than one thread - I've just noticed that my thread about the 1KZ engine is not titled as relevant to LCs.
This is because it used to "live" in a section given over to the Toyota product but now it is all together with "light vehicles": so, to find the earlier discussions, you would have to trawl back through various earlier threads in here.

I was doing the same thing a few years ago; I have threads in here about the Isuzu Trooper, the Freelander and the Nissan X Trail ( I have slept in the back of the latter, using a tarpaulin over the open tailgate as an extension of the flat back).
I used to think that a tailgate type of tent would be something worth trying, attached to any of the above, but I never got around to that before I settled on a transit van with a fold-up-bed and a trail bike in the back.

I would suggest that a light 4x4 van as mentioned above would be a better bet as an extended travel vehicle, as they are quite "car" like to drive now.
The defender is about biggest interior , but not as sophisticated as discovery . Even with a roof tent in Europe its still basically camping , with all the faff of wet canvas ,not really something i noticed traveling in Australia I have mine fitted out to do what you want but its very snug , and means having a safari room attached for dressing room etc .

After a bit more research, and a few shows, the mitsubishi delica seems to be a good compromise, so maybe the Disco is in second place.

I drove all over europe From Italy through most of the easten block contrys austria france ect ect with my wife a then 3 kids and 2 dogs in my TD5 discovery towing a sanky trailer with a roof tent on it doing alot of off road tracks really good ones in Bulgaria and Greece I only had 2 problems i 10,000km one front shock went but it was a brit-part (not a fan) and the sensor on the ACE system came lose and took a bit to work out what the problem was apart from that it was great we where in snow and sun rain and wind on and of road and it didn't miss a beat it was a great trip

We've been all over Europe and Morocco in our Td5 Discovery lt eats the miles in comfort we live out the back of it and sleep on the top we do look after it and tend to use genuine parts we've owned it for about 10 years so we know it pretty well.

The van continues to do a job for me.

The light weight motorbike is in and out of the back in a jiffy; the bed can be used for one up sleeping with the bike still in the van, and two up sleeping is very roomy with the bike outside the van.
It's also handy for carrying pedal bikes around - just throw them in and go, or strap them down if you don't want new scratches on them. :innocent: