Z80s as microcontrollers now exist, if that matters to you. Zilog makes "eZ80", Z8 "Neo", and "Z16" (16 bit architecture) as well as 8051 microcontrollers. You may be able to sample them. They also provide a free compiler and a very cheap programmer.
Compiler/IDE: Search for "ZDS II – eZ80Acclaim! version 5.2.1 with RZK and TCP/IP Object Code" on Google (it's at the Zilog Store but there is no direct link).
I was able to get simple projects running with the Z8 Encore, eZ80, and the Z16 microcontrollers using the linked programmer and the free software.