I've built a profit simulator for SIACOIN mining as I am was interested in purchasing Obelisk miners.

So, I modified datas to fit with this Asic and here we go:
(figures are slightly lowered because simulation was since June and included a decreased block reward as it's stated in SC source code.

Future price : $0.05
Electricity price : 0.18$
% remaining GPU miners (conservative IMO) : 10%
Pool fees : 2%
Investment : 2979$ (A3+PSU+import taxes

If qty sold is : 5000
Net daily reward : 164.21$
Net monthly reward : 4926.24$
ROI : 18.14 days

If qty sold is : 10000
Net daily reward : 82.10$
Net monthly reward : 2463.06$
ROI : 36.28 days

ROI is directly correlated to sia price, so if it reaches 0.10ct, ROI is 9 days for 5k sold, 18 days for 10k sold.