The situation we're finding ourselves in is:
Webhost #1
Serves www.example.com
Webhost #2
Serves www.widget.com
For various technical reasons, we are unable to unify the sites into a single host. What we'd like to do, is make:
www.example.com/widget
Serve Webhost #2's content (dropping the domain www.widget.com). Ideally, making example.com/widget have a CNAME record point to #2's IP would be ideal, but I know this is not possible.
Are we able to make a subfolder in a URL point to another host without redirecting to subdomains? We need the URL structure to remain natural (no subdomains).
Proxy's are not an option, as the two environments are geographically very far apart. (Again, for a variety of technical reasons).
Just put a redirect on www.widget.com to www.example.com/widget.
Drop you widget.com content in the example.com/widget folder on the web server and you should be fine. If you have absolute paths in the widget web content, you will need to update them to be relative paths pointing to /widget.
After some time passes, you can kill the redirect on the one widget.com.
Both apache and IIS make redirects pretty seamless.
Also, if you update the DNA entry for www.widget.com to point to the same IP as example.com, you can tell your webserver to look at the host header and if the host header matches www.widget.com redirect to example.com/widget.
In apache you would setup a virtual host with a redirect, in IIS, you would setup a blank site with host defined in the binding and set the redirect in the site settings.