I sat next to an active 10 GHz op at yesterday's club dinner meeting and he said 3/4" copper pipe makes the best 10 GHz waveguide. so you buy your transmission line at home depot.
the GunnPlexers we designed to operate directly or feed a dish, no additional waveguide, but you needed a 30 MHz IF receiver for WB FM, still need to build those....
back on topic.... if the ICOM thing proves to be real and not april fools joke, I hope they add a 1296 version, that would make it a companion to the IC-705 for VHF/UHF mountain topping & portable.
AA4Q