Someone wanting to extend their life will not waste their time risking it against a 17th level Wizard with 31 Intelligence, and that's even before they're put on an even keel considering how many goodies such a monster will have.
If you want to talk Intelligence, why not get a Steel Dragon Great Wyrm? It casts as a 21st level Sorcerer. However, again, you run into the problem that it is more dangerous than you. And yes, it does have Mantle of the Icy Soul ready for your Shivering Touch, because it's actually played at its intelligence and not WotC's "duh, uh ok I take Weapon Focus for all of my feats" standard feat idea.
Your attitude doesn't help. "because we're min-max" - it might be "what we dotm" but at the same time, we try to do so intelligently - and at the least, telling a Wizard seeking immortality to locate a creature that's more powerful than he is, and ask that he be allowed to give him a pat on the back while you drain his intelligence (provided, of course, he's not already immune to said drain - and he will be, he's paranoid-wizard.com/go-away)
If you're going to do that, get yourself a Neraph with access to Metamorphic Transfer and some ability to change into a Visilight. Use that to bluff and diplomance the target into being your friend, removing his Mind Blank, and then being Diplomanced into Fanaticism. That. Or just be an Ardent using the Epic StP Erudite to get the spell as a Power (doesn't need to be actively involved, just present), and then putting it on a Mantle using the Substitute Power ACF.
That's Min/max and kinda cheesy (requires Spell to Power Erudites to reach Epic levels), but dead easy to do.