Probably this has already been said, even there might be a script or something but as I dont know it, i give you the idea.
I think it'd be great that you could be able to include your own icons on your nick. I.E. if you had an icon call Weee, you could have that icon on your nick by including a code and the name, for example: icon:weee, and then.. it would appear on your nick like the original msn messenger's icons do. Of course, only people with MsgPlus would be able to see it, otherwise, if they dont have it, obviously, they would see the code.
What do you think?

PS: English is not my first language so if i have to explain it again, no problem

By custom icons I assume you mean custom emoticons. Sorry, not possible.

yeah, emoticons, sorry, in spain we call them icons xDD
anyways, thanks for replying!