Methinks mosfets are cool. They don't arc or spark like relay contacts do. If a couple can run an arc welder or plasma cutter, switching your solar panel array should be no problem. Just beware of the datasheets:
FET Current Ratings -- Chuck's Robotics Notebook
If mosfets seem wimpy, there's always the almighty IGBT. For when heavy-duty isn't good enough. These go in EV power modules and Tony Stark's toys and such. Super duper duty.