I recently bought a Tascam 32 and stumbled upon what I believe to be misinformation in this thread. Accoding to the service manual for my 32, you CAN convert the deck from NAB to IEC by switching some jumpers on the internal amp.
From page 39 in the manual of the 32:
Note: If necessary, inter-switching between the NAB and IEC standards can be accomplished by simply removing and repatching the jumper wires on 5 points of the amplifier. The details are explained as a note on the schematic of the amplifier section.
From schematic of amp section:
For NAB Standard: With the A, B, and C jumper connections being disregarded, jumper D is connected to the terminal side of C129 and jumper E to the terminal side of C128.
For IEC Standard: With the A, B, and C jumpers in place, jumper D is connected to terminal side of C127 and jumper E to terminal side of C130.
Now, I have not tried this myself, but it seems straight-forward. This then makes the Tascam 32 a "tape project ready" machine as it is a half-track, 7.5/15ips/IEC compatible machine out of "the box". I hope this may help someone down the road because it took a bit of digging to find out!