Um. The original designs are packed away - I haven't had a playtester or reason to pull them out for a long time. From memory, the most common was to be the 12-ton Striker
6/9
Light Cockpit - 1.5 tons (Think enclosed motorcycle seat. The fluff said it wasn't sealed against water, NBC, or Infernos, but I might re-think if I ever open it back up.)
Armor - I can't remember how much or the layout - I think there were 60 points of armor total, but I can't remember what the IS looked like.
Wpns - Two Medium Lasers, two Small lasers, four RL-10s
The rest of them were deliberately slated for different roles. From memory,
9 T - Scout, 9/14, Beagle AP
10 - ?
11 - ?
12 - Striker (above)
13 - ?
14 - Permanent Air Mech, 6/9, internal mission bay, Guardian
15 - ?
16 - Wrecker/Field Maintenance unit, 2 lift hoist, fluid gun
17 - ?
18 - ?
19 - Assault/Fire Support, Large laser (I can't remember if its an ER)
I can PM you the construction rules if you want to make your own. Keep in mind they belong in the AU for a reason, though - they're vicious little killers, but there are other tech items in the AU that make them less dangerous, like the Cassette missile system that fires 30 SRM/40 LRM, etc.