Sort of related, I realized that a conventional platoon of Mechanized Clan Infantry would be able to use ProtoMech Autocannons. This matters because the ProtoMech AC/2 has a max range of 20 hexes. My platoon could field seven ProtoMech AC/2s. So essentially the defending CI platoon would be a 20 hex ranged SRM-7 battery.
Probably the only place to see it would be with Clan Blood Spirit's armed civilians, but it could be a good supplement to any other conventional platoons that use heavier guns like Gauss Rifles or Ultra ACs.
Though now that I think about it some more, maybe the Ghost Bears and Ravens would use something similar for their Inner Sphere troops. Have to think about this some more.