Alex,

I agree it would be an improvement the replace the cork "lid" with a chain-secured, screw-on stainless steel stopper that would allow leakproof water carrying - and perhaps incorporate a pressure release / tea kettle whistle type feature.

Your suggestion to turn the kettles into samovars by adding folding spigots would seem to introduce new problems of packing and transport, as well as vulnerability to damage.

A removable top lid for the fire chamber "volcano" might make transport of items inside the chamber more handy. A second removable lid that opened the top of the water chamber would ease filling, emptying, and cleaning it - and might allow its use for cooking. A lid that incorporated both features seems possible, though might challenge the stability of the overall strength of design.

Have you sent your suggestions to any of the three kettle companies?