Apple upped the ante by introducing the 68LC040 processor on the Duo 280 and 280c in May 1994. (The 68LC040 is a low power version of the 68040 with the internal FPU disabled.) Other than the CPU, this is essentially a Duo 270c.
Like the 270c, the 280c supports 16-bit video if you select the 640 x 400 pixel mode under Options in the Monitors control panel.