We have something built in that can help with this issue. Since the real problem is that IIS shuts down the app if no request is received after 20 minutes by default this causes a neeed to re-JIT when a new request finally comes in, so it makes low traffic sites seem very slow.
Add this to your user.config and then touch Web.config to recycle the app.
<add key="UseAppKeepAlive" value="true" />
It will make periodic requests for the home page of the site before the timeout expires thereby keeping the app awake and already JIT compiled.
Hope it helps,