This is a topic that has come up periodically on a number of boards, TMP in particular over the past few years. Usually someone expresses the opinion that Warner Brothers would sure the a**e out of anyone who made anything resembling the Potter characters even if described differently. A more realistic view is that having kids with glasses pointing wands or on broomsticks is not in itself copyrightable - after all Rowling invented neither wands nor broomsticks - and there have been the odd figure (as mentioned) over the years that could be so used. But figure makers are understandably reluctant to run the risk of being sued by a behemoth like Warner even if legal opinion is on their side.
It would be great to have a range of figures 'resembling' all the main characters from the books and they would, I am sure, sell like hotcakes. As it is many of the minor characters are already available - there are heaps of wizards, witches, werewolves, even a Voldemort type figure (check the TMP posts on this
http://theminiaturespage.com/boards/search.mv). As already mentioned you can also get an approximation of Harry. But a compatible Hermione, Ron and the other kids? Not really. Until someone makes them . . . . .