I've been working on this idea for quite a while, a trooper Proto-Mech for the dark ages that uses the 15 ton chassis cause really its the most efficient ton for ton and you can do some interesting things with it.
Jackal Super-Heavy Protomech
Mass: 15 tons
Chassis:
Power Plant: 135 Fusion
Cruising Speed: 64.8 kph
Maximum Speed: 97.2 kph
Jump Jets:
Jump Capacity: 90 meters
Armor: Standard
Armament:
1 ER Medium Laser
2 Machine Gun
Manufacturer: Unknown
Primary Factory: Unknown
Communication System: Unknown
Targeting & Tracking System: Unknown
Introduction Year: 3145
Tech Rating/Availability: F/X-X-X-D
Cost: 1,735,781.25 C-bills
Type: Jackal
Technology Base: Clan (Standard)
Tonnage: 15
Battle Value: 611
Equipment Mass (kg)
Internal Structure 1,500
Engine 135 4,500
Walking MP: 6
Running MP: 9
Jumping MP3 450
Heat Sinks: 5 1,250
Cockpit: 750
Armor Factor: 67 3,350
Internal Armor
Structure Value
Head 4 9
Torso 15 30
R/L Arm 4/4 6/6
Legs 8 16
Main Gun - -
Weapons
and Ammo Location Mass
Machine Gun Ammo (40) BD 200
Light Active Probe T 500
ECM Suite T 1000
ER Medium Laser T 1000
Machine Gun LA 250
Machine Gun RA 250
So, the Jackal protomech. Armed with a torso mounted ER Medium Laser it at once draws comparison with the Roc, both sporting the ER Medium Laser. While the Roc doesn't quite cost half of what the Jackal does in BV2 the Jackal does come with some other options. The Jackal is faster on its feet, sporting the very nice 6/9 movement ratio, and given that Protomechs don't need to make piloting checks suddenly that speed on concrete is amazing. It does have a 90 meter jump range to help it get over the impassable terrain it can't conquer but don't count on jumping for its agility. The machine also sports a full ECM system and a light active probe, again lending it to the Urban Warfare role. To handle the inevitable infantry encountered it sports a pair of regular machineguns, 1 in each arm, each fed from a 20 burst magazine. Armor is maxed out, meaning the torso can handle 2 full Gauss hits and not breach.