K-Line did a semi-scale Mikado with an oil tender. Most of their semi-scale Mikes were coal, but the MKT one and maybe one or two others had an oil tender. The catalog also said the WP one was an oil burner, but every one I've ever seen had a coal tender. Maybe there was an insert in the box and you could switch, it would be interesting to know that.
You mentioned Sunset and indeed, they have made a couple of nice small oil burners. I'm very fond of my SP Mogul, and many years ago they did a Harriman UP/SP Mikado. Unfortunately that was in the days of QSI OEM and they never reissued it with decent electronics.