The "very high defenses" is the easy part. There are several valid ways to build a ludicrously tough tank, and most Tanker primaries can be built to insane levels of defense and/or resistance without too much difficulty (some easier than others, of course). The "without exhausting endurance" is what will be tricky. But, you might want to be more specific with your question. When you say "without exhausting endurance", do you mean without the use of a "crash" power like Unstoppable, or do you mean without endurance problems in general?
If what you are looking for is a Tanker primary that is tough enough to fill normal Tanker expectations while not really having to worry much about Endurance, give Electric Armor a look. Power Sink is great.
"without exhausting endurance" I mean with all "buffs" turn on my endurance do not get zero and deactivate all. And and i say "VERY high defenses" im saying defenses and not resistances. I mean dodge attacks.
