Satellite-UMTS supports broadcast applications that involve transmission of the same encoded data over channels that may vary significantly. The same code must allow a user with a good channel to recover the information with low complexity, while a user with a bad channel should still be able to achieve an acceptable BER at the cost of increased complexity and/or decoding delay. To this end, we propose serially concatenated multilevel code structures that employ PSK modulation. The receiver has the flexibility to achieve turbo-code, trellis-code or uncoded performance, depending on the decoding effort. Design considerations include the constituent encoder design and the use of a non-uniform constellation. Simulation results investigate the system's performance and highlight different parameters trade-offs.