Also, pardon my low IQ, I think I understand how the head transforms now -_-++
All images from The Gundam Base Side One.
EDITED: magazine scans of more details about Unicorn:
Like what was said on SRW Hotnews: Do you ever suspect this is how MG Unicorn change his face?
Image from SRW Hotnews.
Open the leg armor, and pull the thigh up to reveal the Psycho frame beneath. Does this means the leg must be detached first?
Image from SRW Hotnews.
Part swapping? I don't see any need for that now. Terribly sorry for all the misleading information so far -_-
Image from Hong Kong Model League.
Plenty of tricks with the armaments. Cool!!
Image from Hong Kong Model League.
Also, you can have a look at HCM-Pro Gundam Ez8 and Special Painted RX-79[G] on the same site.
On the other hand, Gunota Headlines reported that 1/100 Kyrios will come in January at the price of 2,730 Yen, along with HCM-Pro Ground Type GM (2,625 Yen).