Same happend to Kirakira Spacy. I guess you just need to repeat it everyday xD I did that and I have Kirakira Spacy in diary/history.
I bought cards and they are quite easy to use. Now I just wait for a girl-tama, but I get boys all the time. Still, now I have Kuchipatchin and it's very very...
Ok, back to Spacy - during King Spacy personality stage bathing didn't work, but when it turned back to normal Spacy - tree bathes and I got Kirakira Spacy.
So I guess you can only get personality stage from "normal" stage.
I got Slim Neene when she got below 25 with weight (when got over 40 later she got fat again), and now I have Spacytchi and it turned into King Spacy after learning all skills. I like it, so I will try bathing him in few days (now he should stay as he is) ;p
I got Yancha Mametchi (Mametchi on motorbike) when i didn't play with him. Then when I took care of him he turn back to Mametchi. Then when I bought the room decoration with "space" motive he got really happy and turned into Mamerabotchi. Thats the first personality stages I got.