In this paper a cross-layer scheduling and slot allocation scheme is proposed, which takes into account both the powerline channel conditions and the delay requirements of multimedia users in order to make slot reservations. The proposed mechanism aims at providing both fairness and efficient slot utilization, since the available free slots are shared proportionally between the contending users of different services. The contending users are scheduled to the available slots according to their priority value, which is computed with the aid of a channel- and delay-aware priority assignment function. The simulation results in terms of packet dropping probability for real time and mean access delay for non-real time services show that the cooperative synergy of the physical and the MAC layers can significantly improve the powerline system performance.