What happened to the SAA1027?
I looked for the SAA1027 using findchips.com and it looks like no one has it.  According to this datasheet from 13 years ago, The SAA 1027 can only provide 0.5 A output current and its inputs require inconvenient voltages: you have to provide it a voltage abpve 7.5 V for it to read as high!  This means it would be difficult to interface it with a modern microcontroller running at 3.3 or 5 V.

One modern, popular way of driving stepper motors is to use the A4983 IC.  It can provide up to 2 A of current per coil, perform microsteps, and it can easily interface with a microcontroller.

Pololu sells a convenient carrier board for it so you don't have to do SMT soldering yourself.  The reprap community uses this board a lot (see here).