It isn't the lensatic'ness of the compass that makes it radioactive - i.e. you can have non-radioactive lensatic compasses. The radioactive part is the glow-in-the-dark tritium which is an (overly) regulated substance in the USA, but really no big deal. You can buy tritium in many forms, even glow-powder, in other countries like the UK. It is not particularly radioactive, so the thieves are unlikely to suffer any damage, even if they were to eat the compass.
You can purchase military grade lensatic compasses from many sources. Here is one for $80: http://www.actiongear.com/cgi-bin/ta...s.tam?xax=6502