The issue with that is that a browser would still need to already be installed and obviously thats not going to happen
There is no easy win for Microsoft, the EU and Opera
Microsoft is not going to ever include setup files for a competitor (unless they buy them out) which makes a ballot screen hard to do.
Providing links to download other browsers, requires IE to be installed, not a solution for Opera.
The only real solution I see to end all of this, is the OEM providers
Having a ballot screen doesn't require a browser at all. I said similar to the search engine option for a reason. Making a program that connects to a web site and retrieves an XML file containing browser name, download link, etc is an easy thing to do. Same goes for downloading the file, the HTTP protocol is pretty simple if you just want to download a file and wouldn't take long to code at all. If I could be bothered I could create something in under an hour that would be a simple working ballot screen with options to download the various browsers.