wow, thank you all for the resonance. 
i really appreciate it and the questions you are asking where the same i´ve asked myself during the building process. 
i´ll answer them right away.   
@V0101_MMaister i use a mixture of airsprings and M-struts ("mechanical airsprings") plus a telescope mechanism for the centering and pressure building. there is no pressure/force on these parts if the pedals are in center position. as you´ve mentioned airsprings alone wouldn´t do the job.   
@Ragtop 
maybe, but not in the near future (moving to another place plus building my own g.seat at the moment, so time is short).   
@Slaw wow, the master himself! it´s like a knightly accolade for me seeing you posting in my threat. you and realsimulator where the main impressions which let me build these pedals. 
now to your questions:   
-i use an arduino + hall sensor for rudder and 2 potis (build in under the airsprings for the toebreakes) for the toebreakes.   
-the pedals are a tough nut (i guess you know it :-D) i don´t think that it would be profitable to sell them on their  own ( material, machine time and working time will summarize to around 350-400€ i guess).   
-i don´t understand you bearing question but i´ll try to answer. 
the 4 main ballbearings for the rudders are from an old snakeboard and are planted with the same mechanism, all other ballbearings (another 8 for the rudder plus 4 for the toebrakes) are grooved ballbearings because they are capable of withstanding radial and axial forces.