Here is a set of metronomes as MIDI files you can play in a MIDI player (such as MIDI Voyager), and play at most any tempo you desire. They were created at 100 bpm, and at that tempo they last 5 minutes.
To set the tempo you want using MIDI Voyager, you set the "percentage" value to be the tempo you want. For example, if you tell MIDI Voyager you want to play at 68%, it plays at 68 bpm.
For your convenience the sound font file is included in the list, as is a compressed zip file containing all the other files, allowing you to do one download to obtain all metronomes and sound font file.