oh dear....well to own up, i have around 150 pin badges (not all rspb i hasten to add) until it got so that they wouldn't fit i used to stick them through the strap on my satchel, then on ribbons hanging off my pin board and then when that finally gave way under the weight i resorted to keeping them all in a bag.
however i reckon you could get a couple of those plastic bead storage efforts and upend it that might work? one badge per little compartment? and you could decorate it if you wanted to!
ther's a link o the sort of thing i mean below, but you can pick them up in model shops and craft shops all over the place!
GJ Beads - Storage box 27 x 19 x 4.5cm