I tried to find some hashing algorithms that would favor RISC processors, since they dominate modern smartphones, but I've failed to find any. If anybody has some info about such algos it would be very nice to share that info here.
Sounds like you may want to have a crack at the Cuckoo Cycle GPU Speed Parity challenge at
https://bitcointalk.org/index.php?topic=707879.msg7996954#msg7996954Among all PoWs, Cuckoo Cycle may be best suited to smartphones since it minimizes computation, and spends 2/3 of its running time on memory latency.