I don't really have any firsthand information for you since I've never cared for a large pond. I have seen windmill aeration systems in some pond catalogs though. I have not seen a large solar system. I've only seen ones that power very small pumps. My page on large ponds is at
http://www.fishpondinfo.com/farm.htmI really don't have any information there but do have links to a few companies that sell big pond supplies including windmills.
If anyone has information or tips to pass on about larger farm/gamefish/natural ponds, I would love to add more to my site on them since I don't have personal experience in that area.