The airframe certainly has the real estate to accommodate a number of systems. The MRTT could also be further developed for limited AW&C - making it truly Multi-Role. However, I suspect there will be a trade-off between endurance/fuel load and ZFW, an A330 AWACS version may carry a maximum of around 80,000Kgs. That would give it a max unrefuelled flight time of around 12 hours, which seems pretty reasonable.