I wouldn't be averse to seeing a few special ships linked to high ranks, as long as they're not vastly superior to existing ones (and definitely nothing better for combat than the Corvette or FDL).
Some possibilities:
Exploration: a large exploration ship commissioned by Universal Cartographics and made available to Elite explorers. Size 8 FSD, jumprange comparable to the Anaconda (but a heavier ship), onboard hangar capable of carrying one Small ship (shuttle / landing craft).
Trade: Panther Clipper. More cargo than existing ships, but not by much (800-1,000t). Requires Elite in Trade. Size 7 FSD, carries one Small ship (can transfer cargo).
Combat: Federation Pocket Carrier, requires both Admiral rank and Combat Elite, good in combat, size 7 FSD, carries 3 Small ships.
Imperial Pocket Carrier, requires King and Combat Elite, lighter and faster than Fed version, size 8 FSD, carries 2 Small ships, jumprange slightly less than Exploration ship.
Alliance Pocket Carrier, no rank requirements, modest toughness and firepower, size 8 FSD, carries 2 Small ships, performance lower than Imperial version but with more cargo capacity (but still lower than a T9). Can only be bought at Jameson Memorial or in the Alioth system, requires Allied status with Alliance.