**I should mention that the excel fig i got this spring died after transplanting it from its pot into a larger one. water was not an issue. It got fairly warm (i forgot to put it in shade) for a while to avoid it going into shock. That being said im not sure why it died, i have transplanted fig trees in early fall without any issues. The one i have recently acquired was quite expensive and really rare so i can not affort to mess it up.**

Hie all i have managed to acquire a fig tree to add to my collection that has some fruit on it. Its currently in a 1 gal pot (likely rootbound) and i want to put it in a 5 gal pot. I don't want to disturb it at all so i am thinking of just burying the pot its in inside a larger 5 gal pot without disturbing it at all. The drainage 'holes' are about 10mm square (about 0.39 inches) and it has 6 of these so it will not have issues sending roots down into the larger pot. I will also be cutting the pot out during winter and then planting in back in the 5 gal container. 

What are your thoughts?

You should be able to remove it from it's current pot without damage. That assumes it's well rooted which you said is the case. It will probably survive doing what you suggest. But removing a rootbound plant from it's pot won't damage it in the least. That's certainly what I'd do.

Don't jerk the plant out by it's stem. Flex the pot some on the sides and then push on the bottom to loosen the plant. It should come right out. If not you can carefully cut the pot off.

I've cut the original container on many occasion in order to avoid pulling the plant out, then I covered the football with soil in larger pot very carefully.
If it is totally dormant, then the chances of shock are almost zero.

Remove the fruit. They aren't going to ripen at this late date. Transplanting should not be an issue, unless the roots are somehow severely damaged.

Hie pitangadiego, im in Australia so summer is starting up around December :). I should have mentioned that. 

Hie ThaiFig, Thank you very much for that excerpt. Its very useful. Looks like i will be doing that method. 

Thank you all for your replies. I'll update on progress.

Hi,
Like written in post #2 - either your current pot is full of roots, and then you can slide the tree out of the pot - don't touch the roots. Put the whole thing in the middle of the new pot and add potting mix.
If the current pot is more dirt than roots, you just don't need to pot up now. Wait one or two months more, and by that time the pot will be full of roots, and you are then spot on to pot up.
Pot in a pot, I would use that for a temporary tree that I planned to give away later or plant somewhere else. I have some with escaped roots, because they are meant to go somewhere else ( the remaining question is : Where the hell !!! )

I wouldn't use the pot in a pot for an in ground tree except if I removed the bottom side completely. The roots can grow big and would become girdled in the future if you put the full pot in the new pot.
I use the pot in the dirt, but that's for rodent protection and to restrict the roots as this is said to have a dwarfing effect on the trees, forcing them into fig production instead of just stem growth.