I have seen some at the Moccassin Kill Preserve in Rotterdam. This preserve is actually named after the pink lady slipper or moccassin flower! There aren't tons, but their are some. Here are directions:

Take I-890 to route 5S west. Go about 1/2 mile on 5S and take a left at Lower Gregg Rd. Continue on Lower Gregg Rd. as it turns left up the hill. About another 1/2 mile up the hill, the road forks. Take the right fork which is Crawford Rd. The trailhead is just SW of midpoint of Crawford Road on the left hand side. There is a sign and small parking area here to help you find it.

Directions Link: http://www.mapquest.com/maps/map.adp?city=rotterdam&state=NY&address=1300+crawford+rd.&country=us&zoom=5)

Good luck,

Channon