Thanks guys for your comments and suggestions ! I will ask builders from my EAA chapter about the experience with local authorities regarding the anti-collision strobes. After a search on electronic components resellers web sites, I am more or less tempted to buy an extra-bright 12V white LED bar and embed it on top of the fin/rudder, under a transparent layer of glass fiber. The flasher electronics itself is not a big deal using off-the-shelf components. For now, I consider placing some light corrugated pipe with a pull tape inside in the volume of the rudder, so the wiring later will be easy.
Stefan Balatchev Ottawa, ON, Canada s_sbal "at" hotmail.com