Something corvette-sized, with a big enough power plant to power broadcasting units that can saturate an entire fight, while counteracting enemy EWAR, scrambling enemy missile locks, and rickrolling the enemy commander.
Edit: In that case, a Constellation has a big enough powerplant to put out some good disruption. Strip out one of the turrets, put on a broadcasting unit, some armored CPU cores in the cargo hold to power it. Retrofit a Corsair for a smaller package.
Double edit: The Bulldog might have a good small-scale scrambler too. Just seems like it would fit in well with the long-range, durable nature of it.