Multiple wireless access technologies and flexible multimedia content processing are converging into single mobile handsets. The combination with the exploding cost of system-on-chip (SoC) design, will make implementation of wireless access schemes on multi-purpose reconfigurable radios the only viable option in the future. In mobile terminals, these reconfigurable radios should couple a high functional flexibility with low power operation. This paper proposes a two-step approach to producing this combination of flexibility and low-power: energy-scalability is introduced in the radio design, while intelligent run-time cross-layer control is introduced to enable low power operation. The concept is validated on a transaction-level model (TLM) of our reconfigurable baseband platform, showing architectural integration and paving the way towards chip instantiation.