Probably not, because transistors produce some heat, and you can't really sandwich surface mount transistors between PCB layers either. You could vertically stack PCBs with some spacing, however, but then normal PCBs will do the job.
It is possible to embed components in the middle of a pcb, but it's a pretty specialist process (read: a pain in the neck because it interleaves the pcb fabrication and assembly stages, making both steps more complicated).