pinkpever's OK, but sounds really... well, pink. <_<
purplepever is a tongue-twister and one heck of a mouth-full.
peverorange doesn't have a good ring to it.
peverred's fairly good. But red gives the thought of anger and thus not so friendly.
peverblue, again, not too catchy.
peverblack sounds emo. Unless that's what the idea was.
peveryellow is too long...
Gah! isn't a recommended username.
Thus I recommend to Stay as pevergreen.

But how about shortening the pever part of your name? Cut it down to just "pev".
E.g. pinkpev, pevkev, pevred, pevrev... well, you get the idea.