As a business opportunity this may sound and be legit. BUT (because there has to be one) you have to ask yourself about the reasons and long term benefits.
If one asks you to publish an app on his behalf but using your account you might be enchanted by short term benefits.
Analyzing it thoroughly in the long run you might be not so enchanted for some reasons that include:
1. you don't have the source code of the app, you only receive and publish so you don't know what's inside
2. while they pay you a one time fee that app may conduct ad serving, shadow install, promotion and so on for benefits thousand of times more than you get
3. related to above that app may have an auto-updater and they can update at some point with code that might not be agreed by Play Store thus having your account suspended or even worse
4. while you can create and confirm a number of developer accounts don't think for even one second that google doesn't know they are related. Once banhammer is released all your accounts will be disabled and you will find yourself in impossibility of even create new accounts
If I missed something please let me know