The Marks Models Windward was my first "real" radio controlled glider (sailplane). It had a 72" wingspan. My old OS 3-channel radio went into it at first, and then was replaced by a Cirrus 4-channel rig. If I recall correctly, the Windward lived two lives - one before the big crash, and the other after (which also eventually succumbed to a big crash). The covering for the first incarnations was silkspan and dope, and then Solarfilm was used on the second. Solarfilm is not sold any more, and as I recall was nowhere near as strong and stiff as Monokote. However, as with most aspects of my aeromodeling back then, the choice for covering materials was based almost entirely on available cash.
In August of 2010, I bought a Windward kit off of eBay. The plans and kit parts are shown below. It will probably never be built - just kept around as a memento of earlier times.
The AMA Plans Service offers a full-size version of plans at a very reasonable cost. They will scale the plans any size for you.
Here are a couple photos that I pulled off the Web.
Marks Models Windward glider kit Marks Models Windward glider (not mine)
SkyBench actually makes a laser-cut kit, with the full blessing of Mark Smith.