Nice idea, a bit impractical at the time tho. Opera is in the business to make money. Making a gratis port to AmigaOS is out of the question. Most of the platforms Opera is on now is because the founding company paid for the port. Only Windows, Linux and Macintosh were done gratis, because their markets are large enough that Opera can guarantee enough income to cover the cost of porting.
Then there's the limitations of the operating system itself. Opera needs key technologies before it will work. AmigaOS, sorry to say, doesn't have it. It doesn't have memory protection, nor even a Java engine. (don't give me the "AOS4 has MP" or anything like that, it's not here yet)
Yes, I've looked into this as well, and it's on the table. if Hyperion's willing to pay, and can guarantee 500k units shipped, Opera will port it to AOS4. Same with Genesi. Still cost them money out of pocket tho.