Manazano Laser have short kits (and indeed occasionally full kits) of many of Peter's designs..
RC groups Carry the online discussion groups where most of Peter's designs are to be found, with comprehensive building and flying hints and tips.
Flying Scale Models carries a monthly article by Peter, together with more than occasional free plans for some of his designs, as well as a plethora of other articles on building, and flying scale, models.
Callie Graphics can supply custom decals for almost anything, if you can get her suitable source material to work from.
Paul Beck Vintage car supplies - for foam cord for those vintage wheels!