The Gill Spary Top is the best I have found,
http://www.gillna.com/dinghy/dinghy_4352.php
You can buy it for about $68 locally, mine is 5 years old now. I wear it by it's self or in a layer process including a combo of the following:
warm poly diver skin (full one peice by Henderson Aquatics) no restriction at all.
shorty wet suit
with these three items you are good to go in all but the worst of days here in central Florida.
No problem with waist Harness. It has a tight rubber area around the waist and wrists you can stay pretty dry in it if you don't crash bad.