it's possible,
You'll need to download the GDK (graphic development kit) from the members area at vbulletin.com first. You'll also need to download some kind of graphic editor that'll allow you to import .psds and the knowledge to re-colour them.
If you feel you cannot or don't have the knowledge in re-colouring them from their default colours your best bet would be to request for the re-colouring of the forum status icons to the colour you desire and I'm sure someone will come along and help you with that.
Ensure you post your request (if you going to make a request) in the
Graphics request Unpaid forum.