After organising an expansion of our offices and warehouse i have finally been able to catch up on things.
Hadn't forgotten about this thread as i'm the kind of guy who hates loose ends. Unfortunately i'm unable locate the specific sticker you are after but i have found a site that may have the answer.
http://www.bumperactive.com/make_a_bumper_sticker.jsp
To be honest i havn't spent much time looking at the site but it seems like the only viable answer in your situation.
Hope this will be of help to you mate.