Depending on the inverter, you may have to go that high anyway. Pure grid-tie systems (no battery bank) can have quite high voltages coming in from the array. Some of them won't start working at all until the DC voltage rises to about 250V.
If your system is battery-based or just uses a lower voltage, then you can't (feasibly) go higher than the max the inverter can handle. The inverters like this that I know of are generally around 150VDC max - and don't exceed it, or poof!
As for multiple conductors to the inverter, you can also just combine them at the array with a combiner box (a bit like a breaker panel, even has breakers for each string) then run the total power back on a single set of wires. You just have to size the home run properly for the current required.