1.2G S4 CPU(lol?)
13M cam f/2.0(same as M7)
720p front cam
Sense 5.0 on JB4.2
The CPU is same as One SV(down-clocked S4) but I doubt it very much because it would not make any existing One S customer to upgrade. So, I think the CPU should at least stay the same with One S(1.5G) or little faster(like 1.7G).
I think the LCD should change to SLCD2 this time instead of AMOLED Plus like One SV(4.3" SLCD2). I actually quite like AMOLED on phone because of perfect black but SLCD2(IPS) has better viewing experiences under sunlight which is more important to me. At the end, I don't care if it's still AMOLED or IPS, they both have pros and cons.
I have a high chance to get M4 because I don't want any size larger than 4.3". However, my One S is still lovely and used only 8 months.
I may wait Sony and see, they are also going to out 4.0" ~ 4.3" 720P LTE with ExmorRS, Qualcomm MSM8960T Dual 1.7GHz with Adreno 320 GPU(I think M4 will use 8960T). Model name: C5302, C5303, C5306 (Code name:HuaShan).