Could/will evolution eventually lead to a single "perfect" self sustaining species

There's a common misconception about evolution, and that is: evolution "makes things better".
Evolution implies changes, not improvement. And when you talk about evolution in the life context, it is not a oriented process, nor does it have meaning or purpose.
What is called "evolution", is actually just the sum of randomic events, where the most fit inviduals are able to cope with the changes in the environment e propagate.
If you think in this way, you'll easily see that "evolution" cannnot lead anything anywhere.
Now, answering your question about a perfect seulf sustaining species: not. Well, any living organism has to get it's energy from an external source, and even plants depend on the nutrients on the ground to make their "food". So, if you think "self sustaining" as something like "perpetual motion" means in physics, it's just impossible.

No organism is self-sustaining or will be self-sustaining because life regulates life and something has to get energy from something that is organic. But I believe it is highly possible, if we don't kill each other, for humans to evolve. I do think that the most perfect organism will evolve from humans since we are the most perfect currently. Primates, specifically animalia, chordata, mammalia, primata, hominidae, homo, sapien (human) or animalia, chordata, mammalia, primata, hominidae, pan, troglodyte(ape) are the most mentally and technologically developed living organisms and so it only makes since that the next best thing would be a product of our kingdom, phylum, class, and order.