Superspud,
Not sure if you're still interested, but I found a map shop in Ontario that has a map of Spray -
http://www.fishingmapsplus.com/
Not sure of the level of detail, but this is from Lorne, the owner:
"I previewed the maps....Spray Lakes Reservoir map will certainly be pleasing to you....plenty of detail...looks like the deepest spot is 60 metres."
Not sure if this would have more detail than the sunsite map. I've been talking to a woman at TransAlta who may have something, but if they don't I'll probably order one from here.