Here are some of the camelback plans that have appeared in model train mags:
Erie camelback articulated, (0-8-8-0, L-1, simplistic plans), RMC February 1955, p. 22 Photo at: http://www.mrmuffinstrains.com/TrainPictures/Prototype%20Erie2601.jpg
Reading camelback 2-8-0 Class I8sa, Baldwin 1905, MR June 1972, p. 56
Reading 0-4-0 switcher, A4a (4 wheel tender) and A4b (8 wheel tender), MR July 1974, p. 56
Photo – A5 0-4-0 http://www.rr-fallenflags.org/rdg/rdg-s1159o.jpg
Lehigh Valley’s 2-8-2 Camelbacks, plans and photos, MR, February, 1979, p. 89
Reading Camelback Americans, Class D-8c, circa 1911, MR, December 1982, p. 102.
Lehigh Valley Camelback Pacific and Mikado, (simple add-ons to Mantua camelbacks), MR, August 1984, p. 68
Reading RR Atlantics, (circa 1905), MR, February 1988, p. 89
Philadelphia & Reading 4-4-0 of the 1890s, info and plans, MR, April 1992, p. 93