Here are a couple of possibilities (not earthshaking):
http://georgianjunkie.wordpress.com/page/2/ (pretty far down the page–right after a blurb about Tarleton)
You could also try a google image search for “16th light dragoons uniform 1776” and “17th light dragoons uniform 1776”. You’ll a lot of dreck (including pics that have absolutely NOTHING to do with the subject!), but there will also be some useful information.