This build is based on (yes, dranozir's again) "Bullybrawl" build for Clan's version of Orion. Since everyone knows that IS tech is worse than Clan one, I had to use some of my creativity to try to keep the layout (and DPS in less rate) the same as original. But remember - this build is slower and have less DPS than original clan build.
I would consolidate the MRM 10 into a MRM 30. This mech runs cooler, and with the missiles in your left torso they will allow you greater freedom to sacrifice your arms in a brawl, and allow more freedom to fire over obstacles. I had to sacrifice a little armor in the legs, but most of the weight difference was made good by switching to light-ferrous armor.