I've has some success of 4000t> ships armed with a few box launchers and a cloaking device. Carry them into system on a carrier, drop them off somewhere, and let them take a few potshots at some enemy civilian ships.
Size 6 missiles (maybe size 4) are the way to go with them though, and since they're box launcher-ed, you can toss out quite a few of them from even a 4000t ship (mind you, early on, like 1k of that is the ships cloak module itself)
But all in all, they aren't that effective due to the NPR wealth mechanics. And they're not good against enemy warships either (unless the target ship is alone, and not bristling with AMMs)
I-U class Hunter 4,000 tons 94 Crew 769.6 BP TCS 16 TH 84 EM 0
3000 km/s Armour 1-22 Shields 0-0 Sensors 77/1/0/0 Damage Control Rating 3 PPV 14.4
Maint Life 3.46 Years MSP 361 AFR 42% IFR 0.6% 1YR 46 5YR 690 Max Repair 210 MSP
Intended Deployment Time: 12 months Spare Berths 2
Magazine 96 Cryogenic Berths 200
240 EP Ion Drive (1) Power 240 Fuel Use 48% Signature 84 Exp 10%
Fuel Capacity 345,000 Litres Range 32.3 billion km (124 days at full power)
Size 6 Box Launcher (16) Missile Size 6 Hangar Reload 45 minutes MF Reload 7.5 hours
Missile Fire Control FC0-R1 (1) Range 690k km Resolution 1
Stealth Launched (16) Speed: 12,000 km/s End: 44.1m Range: 31.8m km WH: 9 Size: 6 TH: 56/33/16
Thermal Sensor TH7-77 (40%) (1) Sensitivity 77 Detect Sig Strength 1000: 77m km
Cloaking Device: Class cross-section reduced to 20% of normal
Missile to hit chances are vs targets moving at 3000 km/s, 5000 km/s and 10,000 km/s
This design is classed as a Military Vessel for maintenance purposes
There whipped 1 up right there. Note that this is EXTREMELY low tech (done with SMing in all tech less than 10001rp. Its a race that I threw into my game for the sole purpose of culling my civilian shipping a bit. Help pull back the reigns of lag and such) The cloak in particular is very large for the ship, and the missile tech is pretty meh.
But a couple important points. While it probably won't be taking much down on its own, a couple of these can reliably take down a few enemy civilian ships. Note the Cryo Berths? Those are so you can rescue the survivors (intel anyone?)
Its not super great at detecting stuff, but most of what it will be going after will have fairly large thermal signatures.
Also the missiles I threw together for these things are rather garbage intentionally (on the accuracy front) to give my "defenders" more of a chance. So you might consider reworking them a little.
Other thoughts are. You CAN do a reduced size launcher version with a magazine (a gang of them is still effective, and a similarly sized and stealthed ship could act as an ammo collier) however the striking power is greatly reduced (this one for example can run with 4-6 min sized launchers, and carry 24 missiles. The collier I threw together can carry 48 more in a ship with the exact same detection characteristics, and I threw in an additional maint storage, cause its just kinda a support ship).
But all in all, not too much is gained. If you're trying to get too close to an enemy homeworld, this is easy pickings for fighters and FACs. And with the thermal output of the ship at top speed, a basic single DST will pick it up at ~30m, and a lot of NPR planets I've come across often have well over 10-20DSTs (so more like 300-600m).
However, other food for thought. with its TCS of 16, a fighter resolution AS of size 10 (quite a bit larger than what most NPRs will be carrying) of equivalent tech will be picking it up from ~30m, and dedicated 16 resolution sensor from 40m. So going by normal NPRs who regularly use 5-10k resolution sensors, of size 2-3. You can actually sneak these in surprisingly close to enemy fleets out on the prowl.