I threw a sample of what I think of as a "proper escort" together using CryHavoc's spreadsheet.
Class/Model/Name: Escort Ship
Tech: Inner Sphere
Ship Cost: $9,913,580,000.00
Magazine Cost: $5,600,000.00
BV2: 83,486
Mass: 500,000
K-F Drive System: Compact with L-F Battery
Power Plant: Maneuvering Drive
Safe Thrust: 5
Maximum Thrust: 8
Armor Type: Lamellor Ferro-Carbide
Armament:
160 Laser Large ER (IS)
40 Naval Laser 55
20 Capital Launcher AR-10
4 Screen Launcher
Class/Model/Name: Escort Ship
Mass: 500,000
Equipment: Mass
Drive: 150,000.00
Thrust
Safe: 5
Maximum: 8
Controls: 1,250.00
K-F Hyperdrive: Compact with L-F Battery (12 Integrity) 231,250.00
Jump Sail: (4 Integrity) 55.00
Structural Integrity: 75 37,500.00
Total Heat Sinks: 1500(3000) Double 908.00
Fuel & Fuel Pumps: 2500 points 1,020.00
Fire Control Computers: 16.00
Armor: 750 pts Lamellor Ferro-Carbide 750.00
Fore: 140
Fore-Left/Right: 125/125
Aft-Left/Right: 125/125
Aft: 110
Dropship Capacity: 0 0.00
Grav Decks:
Small: 2 100.00
Medium: 0.00
Large: 0.00
Escape Pods: 20 140.00
Life Boats: 20 140.00
Crew And Passengers:
41 Officers in 1st Class Quarters 410.00
104 Crew in 2nd Class Quarters 728.00
91 Gunners and Others in 2nd Class Quarters 637.00
# Weapons Loc Heat Damage Range Mass
40 Laser Large ER (IS) Nose 480 320 (32-C) Long 200.00
40 Laser Large ER (IS) RBS 480 320 (32-C) Long 200.00
40 Laser Large ER (IS) LBS 480 320 (32-C) Long 200.00
40 Laser Large ER (IS) Aft 480 320 (32-C) Long 200.00
10 Naval Laser 55 FR 850 550 (55-C) Extreme-C 11,000.00
10 Naval Laser 55 FL 850 550 (55-C) Extreme-C 11,000.00
10 Naval Laser 55 AR 850 550 (55-C) Extreme-C 11,000.00
10 Naval Laser 55 AL 850 550 (55-C) Extreme-C 11,000.00
5 Capital Launcher AR-10 FR Extreme-C 1,250.00
5 Capital Launcher AR-10 FL Extreme-C 1,250.00
5 Capital Launcher AR-10 AR Extreme-C 1,250.00
5 Capital Launcher AR-10 AL Extreme-C 1,250.00
1 Screen Launcher FR Short 40.000
1 Screen Launcher FL Short 40.000
1 Screen Launcher AR Short 40.000
1 Screen Launcher AL Short 40.000
Ammo Rounds Mass
Capital Launcher Barracuda Ammo 50 1,500.00
Capital Launcher Killer Whale Ammo 50 2,500.00
Capital Launcher Barracuda Ammo 50 1,500.00
Capital Launcher Killer Whale Ammo 50 2,500.00
Capital Launcher Barracuda Ammo 50 1,500.00
Capital Launcher Killer Whale Ammo 50 2,500.00
Capital Launcher Barracuda Ammo 50 1,500.00
Capital Launcher Killer Whale Ammo 50 2,500.00
Equipment Mass
Naval C3 5,000.00
Cargo, Standard 3,736.00
Defensive Ammo Rounds Mass
Screen Launcher Ammo 10 100
Screen Launcher Ammo 10 100
Screen Launcher Ammo 10 100
Screen Launcher Ammo 10 100
That's sort of the "light cruiser" approach - it's pretty fragile against battleships, but it packs a punch, has good speed and support abilities, and it can take on whole squadrons of fighters at once from all angles. All for a total cost of under 10 billion. I'd probably divide all the weapons into bays of 5 each, which would be enough for the LLs to hit fighters damned hard without over-concentrating your firepower too badly, and enough for the big guns to put the hurt on DropShips or smaller WarShips, especially if you turn broadside to them(a full broadside is 185 capital-scale damage, which is enough to breach a McKenna in one round if everything hits it on the nose).