The Redmax is pick of the litter. Zenoah/Komatsu is the parent company of Redmax, and the 2300 sounds like it will be very much similar to a G-23.

The John Deere 300CS sounds like a rebadged Echo CS-300 chainsaw. If so, those will be light and powerful 30cc conversions, assuming you can either source or make your own conversion parts.

The BR48 sounds promising too. Blower motors tend to be fairly powerful engines to, often tuned for RPM than down low torque like chainsaws. Plus the crankshaft may be lighter-duty because it doesn't have to withstand the shock loads that chainsaw see.