I have done a couple of kitchen remodels where the use of Wiremold boxes against the cabinet bottoms was planned from the get-go. One in particular stands out, and it's how the demolished kitchen had been done.
For the receptacles, I stubbed out the 12/2's as I would for under-cabinet lighting, had the cabinet guy drill holes in the cabinet back panel, and mounted shallow 1-gang W/M boxes against the panel back, facing down.
The receptacles were protected by GFCI receptacles installed in wall outlets elsewhere in the kitchen, so I wouldn't need deep W/M boxes under the cabinets, which would show from under the 1" cabinet skirt.
The under-cabinet pucks (I prefer fluorescents, but . . . ), each with attached 18/2 lamp cord, were wired into separate, blanked shallow W/M boxes. I used hot-melt glue to affix the 18/2 to the cabinet bottoms.
The switches were installed in their own 2- and 3-gang W/M boxes. To protect all of the NM and 18/2 from the edges of the W/M box front KO's, I slit 1"-long pieces of 1/8" ID rubber tube to make grommets.
Not suprisingly, the inspector didn't like the installation methods, but then he also wanted GFCI protection of a built-in desk at the far side of the kitchen, claiming it looked like the countertops to him.
I was well prepared with my read of the NEC about everything I did, and I asked him to bring his boss to the jobsite. I showed him my notes, and he agreed that everything I did considering what I had to work with.
As for getting stuck between the customer, the GC, and the designer, the best defense is a good offense. I tell them the requirements, what the options are, and ask them to let me know when they come to an agreement.