Sort of. It's a "site down for maintenance" setting that will display a static htm or html page that you specify. The setting for this is in the web.config (search for SiteDownForMaintenance and set the value to true). This brings the entire site down though, so if you're looking to work on the site you'll need a sandbox to access or you may just want to turn the buy buttons off so customers can't order while you work on the site.
<a href="http://www.aspdotnetstorefront.com">Shopping Cart Software</a>