Do You Have Several Million Dollars For Development
I'm sure it could be done. The thing is that this isn't easy and would be extremely costly. Also if it matters to you, it would not be approved for Mac app store distribution.
If you have some personal need for Rosetta, why not just setup a older Mac with it, and use the screen share option to access that, or just sit down in front of it. For Rosetta apps, you'd probably get better performance by using an older PPC machine.