As far as i can see (google) it is. It looks like the functions described as "Visio technical" are now standard functions within Visio.
A few examples:
- templates for HVAC, Piping and instrumentation etc.
- importing dwg files
- reporting functions
- layer handling...
Looks like Visio Technical is long gone...
Intel Pentium (minimum) 166MHz or better CPU recommended
http://visio.mvps.org/History.htm looks like Technical disappeared around 1999
March 30, 1999: the high-end eVisio Everything package, which includes every shape, wizard and add-on that is currently available in Visio Standard 5.0c, Visio Technical 5.0 Plus and Visio Professional 5.0c.