In the spirit of the challenge, I will refrain from pointing out that XLFE, LFE or Endosteel are all technically 1 item O:-) Consider however:
Take one Awesome 8Q,
-minus 0.5 ton armor, 5 heat sinks (23 total), small laser
-add Radical Heat Sink System, 2 medium lasers
Round 1, run and fire 3 PPCs, heat 32, sink 23, balance 9 heat
Round 2, run and fire 3 PPCs, heat 9+32=41, activate RHSS, sink 46, balance -5
repeat...
You can add the MLs and really punish someone at the 3-hex sweet spot. Alternatively, take the same Awesome 8Q, but instead
-minus 0.5 ton armor, 1 PPC, 6 heat sinks (22 total), small laser
-add Radical Heat Sink System, 10 medium lasers
You now have a Warlord.