I have never had any success with distortion effects on the flute. It's always caused feedback.

I used to play with a Roland GP-16 guitar processor, which gave me a lot of fun delay, reverb, chorus, and other effects besides distortion. I now use an Alesis Microverb. You can get those used pretty reasonably.

I've used a ProCo RAT distortion on flute, but under controlled Home studio conditions.
I recorded the output of a small guitar amp in another room.
An Ibanez stomp-box stereo delay has also served well, in ensemble situations. The Roland products are probably better.

The compression which is part of this type of guitar disortion makes for a very Cheesy sound. Much like a flute played through a kazoo.
Stereo Delay effects like reverbs, echoes, chourus' and flanges, sound more musical.
Having a transducer inside the flute could eliminate feedback problems.
Using an old Leslie rotating speaker would be a very cool effect.
For distortion, i would like to try an array of speakers modified with little bells and rattles to create a buzzing sound.
Allessi microverb is a good way to go though.