Basically, i feel that at low elo, you can't rely on anyone to even contribute to a win. This observation has led me to want to play a tank or support that can somewhat carry a team to victory.

I was considering Mord, for obvious reasons. Or Nasus / Alistar.

Anyone have any suggestions or experiences that would help get into a bit higher elo?

Nocturne.

If you can get a good tank every game you win chance will increase greatly. This is why I unlocked all the tanks asap. This will not work as well in mid-high elo though so you may need to get some real skill

Morde for sure, only advice i can really give is don't jungle and try go tanky dps.

Singed is also another great champ with right team behind you

Nidalee top solo.

Get your farm on and steam roll through low elo - even teemo played well can carry.

Edit:

Duo Queue can also raise you up through the ranks.

kassadin its pretty strong early game, a good kassadin will really increase your teams early game strongness not that much of a tank but its not a paper mage. Morde is good as well not so hard to farm and strong tanky capabilities. A champion i like is xin zhao its really strong with full runes and have high attackspeed for hp tankers with mordred or squishy champions and its more tanky that like-champions. Nasus is just good farmed imo. its not that hard to farm him tho but not as easy as morde. and ofc shen a dps shen can do good damage to a team and being tanky at the same time.