Emma switched minds with Iceman once, more or less possessing his body to move around and using his powers.
 
Can she possess someone now, while still controlling her own body? Or would she have to make a complete mind-switch again?

Well now she can't do anything telepathy related since she's stuck in diamond form.
 
But in her own series I think it was the last issue? She took control of her roomate and made her say crazy things while Emma was outside. Hang on, I think I can find a scan.
 
 

Yeah, that whole series was about her getting her powers and discovering what she could do. So I'm sure now she could do something like that easily. 
 
And I agree, it's so stupid how she's stuck like that but whatever lol.

I'm still dying to buy her series... They don't sell it anywhere... and i'm to lazy to check Ebay.. lol

I'm planning on that ^^

Awe :[
 
I want  to read it more badly now XD

I'm pretty sure she can't while trapped in her diamond form, but she used to possess people all the time.  I believe she swapped bodies with Storm back in the 80's.

Emma switched bodies with Storm due to a device she created I believe, but she has also been in Jean Grey's body as well. While in Icemans body, she used his powers in ways he had never imagined, basically how despite him being omega it's wasted on his lack of imagination, these situations arent really possession, just swaping minds.
 
Anyway yes Emma can posses people, multiple people actually. In New X-men she disabled a huge angry mob outside of the mansion by giving them all orgasms and in Astonishing X-men when a giant mole man monster was attacking New York, she was able to have a group of people quietly and orderly exit a skyscraper, also in astonishing, after wolverine sliced the telepathic scramblers in two heavily arms guards, Emma took control of their nervous system and released them of any pain, however she also instructed them to go to a hospital and to vomit uncontrollably whenever they hear a trigger word, which i cant remember. So not only can she remain intact and active, but her control can be permanent . Oh yea and in New X-men during a press conference with Jean and Beast, a woman called Beast a monster and she possessed this woman as well, then she and jean erased the memory of this moment from the group of people there.

@kimmycat: yeah your right. the covers suck

No, not anyone.

There are many people far beyond her level of power.

I believe she also achived this technologically too via Psy Gun she created back in the Hellfire Club, which she used to swap bodies with Storm at one Point too.