Well I absolutely hate 1vs1s , but a funny (however effective) build for both 1vs1 and 2vs2 with sedna is the "YETIS" one;). Dispite how ridiculous it looks, if you use staff of the warmage you can resurrect the yetis every few seconds and disturb the opponents. Otherwise, u can use the ring of divine might to level up faster/kill reinforcement easily.
If i am not mistaken I even used that build in a practice tournament