Is there something that those methods don't accomplish, that you wish they did? I haven't needed a high level npc yet, but I know that it's in my future, and I was just planning on manually setting levels and abilities.
Hell, I think I'd just scrape the idea of making a full levelled npc, and instead making a statblock with values in the ballpark, and making attacks and abilities that I think the NPC should have.
For example, instead of a full spell list, what is something a wizard should do, to feel wizardly? Fly? Yes! Throw fireballs? Oh yes! Maybe transform someone to a toad? Maybe yes. So they turn into a 20hp flying fireball slingshot that every now and then tries a polymorph.
Almost anything by Ray Porter is incredibly well read and well produced. NOS4A2 read by Kate Mulgrew is solid.