I'm going to stop just short of saying it's impossible, but there's certainly no easy or practical way without doing prep work on the device receiving the MIDI commands. MIDI in an of itself mainly deals with performance data, and that means you're pretty well limited to the capabilities of the device(s) receiving that data.
There probably are some workarounds...I can imagine setting up a synth to generate a sine wave at a given frequency. Then you could program and/or learn what the deviation to that frequency is as you modulate pitch wheel data. Once you had a system calibrated I could see it being a fairly reliable method of generating specific frequencies on demand.
I saw an article where someone was trying to do something like this in order to seed a random number generator. Instead of using a MIDI system, they used a webcam. They pointed it at a lava lamp and wrote software to take a picture, then used the numerical data from the image file as the number generator seed.
I suppose the same kind of randomly generated data could be somehow used to drive MIDI, but I think you'd need someone to write software to act as a go between.