Well, I bought the new 2.5″ 40GB drive today, and am very pleased to say that it works great! I did have a little trouble getting it going at first, but I’m not sure why that was. Maybe the connector was not properly connected, whatever. Anyway, it all works just fine now. Not only does the laptop feel a little bit faster thanks to the replacement, but this hard drive also produces much less noise. For completeness, here are the relevant specs of my laptop in case anyone else wants to try this: Pentium II 400 Mhz, Intel 440BX. However, first a warning: you are responsible for your own hardware. So if it does not work for you, then I am afraid that is your problem and not mine.
Toshiba Tecra 8000 with Toshiba MK4032GAX works!