Check out this one, a CARAWAGON

Land Rover Carawagon 109 111s for sale, classic cars for sale uk (Car: 85672)

Neat little roof on it. Nice traveling wagon.

Or for that really long road trip, you might like this one:

http://www.classiccarsforsale.co.uk/...p/carno/137922

 

Here is what I would do if it were me, buy a good DI, spend the next year or whatever until your trip to fix it up, make it reliable and gather spare parts that you may need.
Learn how to drive it off road, not rock climbing or mud bogging, but good old 2 tracks and deer trails.
If you get a good DI for $2500, put another $1-2,000 into it in repairs, mods, etc. and it is reliable what more do you need?
Yes the diesel would be preferred, but its not like you are going to be 100% alone the whole time.
Bring Jerry cans for fuel, have a 2nd spare tire and remember you can buy tires locally, 16" is a common size.
Then go for it man!!!
Its supposed to be a once in a lifetime adventure, what fun is a adventure in a vehicle that you know if never going to break down?
If you wanted that then buy a brand new 4Runner and go.

 

You actually want him to break down...???

 

LOL!!!

You know what I mean, whats the point of a big trip like this if it is going to be 100% trouble free?
Throw in alittle "what if" and even if you dont break down going through 12 gal of oil on a 3000 trip makes for a better trip if you ask me, telling your grand kids that you drove from FL to Brazil and you had to fix your truck with duct tape and a paper clip so you could finish the trip makes for a great story.

 

"You would not belief how far back I was in the jungle when the Discovery bit the dust. If it had not been for those old timers in their Series that finally rescued me, I never would have made it out of that jungle........" Would probably be the lead-in.

Or "Them guys in their old Defender really saved my butt that time........."

 

There isn't any reason a Discovery 1 can't be made just as reliable, or unreliable depending on the person doing the work, as a Defender.
Short of Salisbury axles, the Discovery 1 was available with the same engine/drive train as the Defender and Salisburys can be fit to Discoveries as easily as they can to Defenders.