A South Windsor site approved for a 198,735-square-foot warehouse went up for sale last week. Two months after a search began for a prospective tenant, Vero Beach, Florida-based Altatwo Realty Co. has begun offering its 16-acre development site at 250 Rye St. for sale. The move broadens the prospective market for the site from occupiers to also include developers, said Mark J. Duclos, president of Sentry Commercial, the firm marketing the property.