Ad Hoc networks still have unsolved fundamental problems such as scalability, security and QoS. Ad hoc networks have to compete with existing wireless technologies that already provide networking capabilities with low cost. The main driver for Ad hoc networks is to have a zero-cost and self-created IP network. We consider scalability as the main inconvenince for future deployment of Ad hoc networks. In this paper we analyse the scalability in a real testbed and we propose a simple and novel solution based on relay nodes. The relay nodes require consuming additional resources that users may not be willing to support. We use Game Theory to demostrate that users will cooperate if a rewarding mechanism is implemented. Therefore, the proposed solution for scalable Ad hoc networks requires a tight interaction between routing and MAC layer to enforce the rewarding mechanism. A new node architecture different from the OSI layering structure is required.