Tom,
Surely one could mount a remote air cleaner down say under the front guard nose with a hose from the air cleaner to the standard air box inlet hose. While yes not standard would be a little difficult to notice and make air cleaner changes easy.
Otherwise I'd be interested in a roll road dyno comparison between the engine with carb trumpets installed and without them (like my Alfa GTV ... similar airbox but no trumpets) and if difference minimal I'd just leave the trumpets off making air cleaner removal considerably easier, I think.
Pete