What Joe said
.
You sould do well with the high sensitivity option TFBs pluged straight into a flash recorder with a decently quiet mic input.
Given the choice of the three recorders you mention I'd go for the Tascam DR-07 because it has a better input stage compared to the M-Audio, records to standard WAV format at higher quality than the Olympus (which is more of a voice recorder), can accept inexpenive SDHC cards (it comes with one) and is a very good deal for less than $150 if you look around. I'd also consider the superior Sony M10, but it is least $200 (and uses more costly Mini-SDHC cards).
I would only like to add that you shouldn't feel you need to record quiet things with so much gain that the resulting recording levels are high on the meters- you certainly don't need to be anywhere near peaking. You can always turn the volume up when you play it back, either on the computer by editing the file, or with the good old volume knob. Doing that can help you make less noisy recordings of quiet material. It's a good approach to run lower-end gear (which often has inexpensive analog front end circuitry that gets noisy at high gains) somewhere around the middle of it's gain range.
If you find you need more recording gain, turn it up, but listen for the point were the noise begins to increase significantly more in loudness than the sound of what you are trying to record. It's somewhat confusing that the noise you'll hear might be the amplified noise of the environment itself, the self-noise of the microphones at verly low levels, or the noise made by the recorder's gain circuitry. Figuring out which is the primary contributor can be somewhat more of a challenge. Using a quieter preamp, possibly with more available gain will only help reduce the noise if that noise is being contributed by the recorder's analog input gain circuitry being turned up too much. It won't help if more of the noise is coming from the environment or the mics themselves. If I had to guess I'd say the mics will probably be the quietest part of the chain.