The thing is, you don't really see much of an uptick in speed as you progress up the tech tree unless you intentionally build flimsy ships and don't increase their ordinance much. You still run into the dichotomy of "Are they fast enough to close the gap?" vs. "Are they well-protected enough to survive doing so?" with the added bonus of "Can they do appreciable damage when they get there?" Here's what I'm using at the moment as a dedicated beam skirmisher with self-defense capability (it's mainly for killing Swarm), and my newish carrier PD escort.
Anthalos class Light Cruiser 12,800 tons 392 Crew 11570 BP TCS 256 TH 256 EM 0
12500 km/s Armour 8-48 Shields 0-0 Sensors 32/1/0/0 Damage Control Rating 36 PPV 73.12
Maint Life 1.78 Years MSP 3390 AFR 218% IFR 3% 1YR 1323 5YR 19845 Max Repair 1100 MSP
Intended Deployment Time: 60 months Spare Berths 0
800 EP Solid Core AM Drive (4) Power 800 Fuel Use 20% Signature 64 Exp 10%
Fuel Capacity 1,000,000 Litres Range 70.3 billion km (65 days at full power)
Twin Karkasy-Tahril 15cm C10 Extreme X-ray Laser Turret (6x2) Range 480,000km TS: 20000 km/s Power 12-20 RM 9 ROF 5 6 6 6 6 6 6 6 6 6 5
Orion Megacorp 52cm C10 Extreme X-ray Laser (1) Range 480,000km TS: 12500 km/s Power 71-10 RM 9 ROF 40 71 71 71 71 71 71 71 71 71 63
Astaroth Incorporated Fire Control S04 240-20000 (3) Max Range: 480,000 km TS: 20000 km/s 98 96 94 92 90 88 85 83 81 79
Kyras-Vandis Engines Limited S-C A-M Power Plant (13) Total Power Output 130 Armour 0 Exp 20%
Ectelion-Ekimus Active Search Sensor MR25-R1 (1) GPS 80 Range 25.6m km MCR 2.8m km Resolution 1
Darius & Temetor Thermal Sensor TH1-32 (1) Sensitivity 32 Detect Sig Strength 1000: 32m km
ECCM-5 (1) ECM 50
Guardian class Escort Cruiser 31,250 tons 567 Crew 7828 BP TCS 625 TH 5000 EM 0
8000 km/s Armour 10-88 Shields 0-0 Sensors 320/1/0/0 Damage Control Rating 40 PPV 218.79
Maint Life 1.06 Years MSP 2566 AFR 781% IFR 10.9% 1YR 2284 5YR 34264 Max Repair 1600 MSP
Intended Deployment Time: 60 months Spare Berths 0
Cryogenic Berths 200
Orcus-Morax Research Inc 1000 EP AM-S-C (5) Power 1000 Fuel Use 2.21% Signature 1000 Exp 5%
Fuel Capacity 1,000,000 Litres Range 260.6 billion km (377 days at full power)
Triple Fabian Weapon Systems Gauss Cannon R5-100 Turret (9x15) Range 50,000km TS: 20000 km/s Power 0-0 RM 5 ROF 5 1 1 1 1 1 0 0 0 0 0
Endanor-Cain Sensor Systems Fire Control S01 60-20000 (3) Max Range: 120,000 km TS: 20000 km/s 92 83 75 67 58 50 42 33 25 17
Tahril-Balian Active Search Sensor MR512-R1 (1) GPS 1600 Range 512.0m km MCR 55.8m km Resolution 1
Sanguinius-Pertinax Syndicate Thermal Sensor TH10-320 (1) Sensitivity 320 Detect Sig Strength 1000: 320m km
ECM 50
Still on my CV-heavy campaign so I don't get much use even out of PD ships since most of my combat takes place several billion km away from my task groups. That Anthalos is actually the largest, best-protected warship I have, most of the others are either missile skirmishers or dedicated support ships. I'm still relying on fighters for exactly the reason I outlined above: they're fast, hard to hit, and ultimately disposable.