Hmm.... what would make a particularly grand Twinned spell? With the (+4?) spell level adjustment, for the most part, that means 5th or below. But wouldn't a Twinned Simulcrula (11th level spell slot, sadly) of yourself (and your Familiar - or better, have the Simulcrulas Summon their own - much less expensive) just be fun? Everyone runs Disguise Self all the time, keep everyone Mind Blanked, and good luck figuring out who's who. Also handy for Crafting (hey, they get feats, they just can't learn.... hmm... Simulcrula Artificers..... is the Craft Reserve of a 10th level Artificer > 1,000 xp?).