Is there a c# wrapper available for the Salesforce REST Api?

A .NET tool kit was announced by salesforce.

"The Force.com Toolkit for .NET provides an easy way for .NET developers to interact with the Force.com REST API using a native libraries."

https://github.com/developerforce/Force.com-Toolkit-for-NET/

If you're looking for a Salesforce's REST API client library, take a look on SalesforceSharp.

It supports create, update, delete and query records from REST API.

Create

client.Create("Account", 
   new { Name = "name created", Description = "description created" }));

Update

client.Update("Account", "<record id>", 
   new { Description = "description updated" }));

Delete

client.Delete("Account", "<ID">);

Query

var records = client.Query<Account>("SELECT id, name, description FROM Account");

Nowadays it supports username-password authentication flow, but others flows (web server and user-agent) can be created and injected.

I was really hoping for something that would parse the WebResponse into classes representing the SF resources returned, and have solid error handling - the tedious stuff :)

This exists - it's called the SOAP API :) Seriously though, if you are doing server-side integration and want typed generated classes and solid error handling, SOAP is your pony.