I suppose that then I'd need to find a supplier of red handsets, or get
a can of red paint. :- )
Don't discount that idea. Lately I've been watching The Ben Heck Show (http://www.element14.com/community/community/experts/benheck). Many of the shows are all about taking some piece of electronics (often a video game), and repackaging it, usually smaller and portable.
If you already have a supply of good looking red analog phones, it wouldn't be that difficult to rip the insides out of a VoIP phone, ditch the keypad, and repackage it inside the old red phone.