My app is based on Silverlight + .Net Ria Services which at the moment requires full trust. Is this supported by Winhost plans?
Yes you can change the trust level on your account. By default it is set to 'Medium' but you can update it in your applications configuration file. Try looking at this kb article. http://support.Winhost.com/KB/a657/changing-the-default-aspnet-trust-level.aspx