This is the cheap cheap end of the scale but I've used it in the lakes and locally at christmas with a tarp. Condensation was a problem in the lakes as I had it all zipped up. At christmas the door was open and no problems.
http://cgi.ebay.co.uk/Pro-Action-Sy...re_HikingCamping_Tents_JN&hash=item563f52229d
http://cgi.ebay.co.uk/Pro-Action-Sy...re_HikingCamping_Tents_JN&hash=item563f52229d