The flowers of P.utricularioides were described by McDougall (the guy who collected them back in the 50's) as "scarlet-red". For some reason I had in my mind that it was more like the color of P.crassifolia, which like P.laueana is very close to P.utricularioides. But it sounds like it is actually intermediate between P.crassifolia and P.laueana.
When I visited the P.laueana site last April, we did find a few flowers which could be called scarlet I guess. Check out this picture on Eric's website which I took of P.laueana last year.
Check out the flower on the lower right. This is probably close to the flower color of P.ruticularioides. Wow, it sure must be a fantastic plant, I wonder when somebody is gonna finally return to the Sierra Azul to photograph this species and hopefully introduce it to cultivation...