Peter , before you jump in the company 60dbm.com out of Ukraine but still working has some nice solutions specifically set up for the machines like Hermes Light and even lower power Qrp transmitters . if you will accept 100W out then for 2-4mW in you have a high quality solution using modern components. These boards can be bought as modules or fully built up with auto frequency detection, heatsinking and most importantly a full set of LPFs. What they don't seem to have is high SWR shutdown. The basic board that goes in amp below costs $250 without heat sink and filters . if you used a splitter-combiner design you'd be looking at abt 180W out for 8mW in.
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100 Watt HF/6m Power Amplifier for Yaesu FT-817, Icom IC-703/705, Elecraft KX3, automatic band switching
$399.00
100W HF/6M power amplifier,? auto band switching
Timothy Fidler