You mention renting a bigger chain saw. How big of a chain saw do you have now?

With a 26 inch diameter this tree could be felled by a chainsaw with a 16 inch bar -- if you worked slowly and carefully and kept the chain sharp. Keep plenty of wood wedges on hand to keep the kerf open as you cut.

After that you would need to remove the stump, which would be a chore in itself. Do you have any friends with bulldozers? It might be easier to push the trunk over and unroot the thing all at the same time.

Something I've thought of trying, but have not quite figured out, is the idea of using a chainsaw milling attachment on a vertical tree instead of a horizontal log. The idea would be to reduce the standing tree trunk to boards which could be easily removed. Since there would not be any felling cuts, there would not be the loss of so much wood at the base of the tree, so you could get longer boards and the remaining stump could be almost at ground level.

If you started the chainsaw at the top of the tree it would cut downward by gravity, while following the track of the chainsaw milling device.

If you wanted to try something like this, you could try to cut the trunk into quarters by making freehand cuts with your existing chainsaw. These could then be resawn on a bandsaw or a large tablesaw, or split with wedges.

It is worth the effort to try and salvage as much wood from that trunk as you can. After all, wood costs money, and money doesn't grow on trees.

PGJ