It all depends on how much you want to run on them. In some cases they are use to supplement, only providing 20% or so of needed power. In other cases they can provide more power than needed - this may result in the local utility company installing a 2nd meter to credit the owner (think of it like being your own mini power plant).
In a really ideal set up someone would use multiple methods of self sustainable energy production - solar water heater, solar panels, geothermal, passive solar, etc. Relying on just solar one would have to install a battery bank that would cover any possible shortages of sun for whatever reason.
As for particular manufacturers I don't know any off hand but here's a start for some research,
Solar Energy Companies
USGBC: U.S. Green Building Council
I would talk to a few local Architects and Engineers as well, might be someone can point you in a good direction.