I think Opera has a chance to do something really awesome. Assuming that the technology was possible.
They should release a browser with Opera, IE6, IE7, FF and Webkit rendering engines built in. They should enable a <META> tag to indicate on the page WHICH rendering engine to use. Default would be Opera, of course. Additionally, add profiling (like firebug) to allow you to compare different engines on the same page.
Benefit #1: I could use this as my development testing. It’s much easier than trying to open 5 different browsers in Virtual PC.
Benefit #2: Publishers could start to put that META tag on pages and say, “this is the preferred browser. Render the page in it please”. This would VASTLY reduce the QA testing done on sites. It would also allow some browsers to innovate and add new and unusal features. Standards wouldn’t matter as much. You could focus on the browser that works best for the kind of site or application you want to deliver.
Benefit #3: Opera would make a splash and a bold statement. They need to get their profile up. Webkit is making alot of noise and FF/IE are the leaders. Opera needs to stay relevant.
The Opera folks had been kind enough to pay attention to the indexOf issue. I hope they think about this possibility.