Here is a patch I developed for a specific project, but I think it's quite interesting in itself to get strange soundscapes and so I thought I'd share it.

The idea developed from this spectral delay patch, with the difference that the selected frequency bands of the input signal, rather than being delayed, are sent to two convolution reverbs (which can be set to work in series or parallel). With the right kind of impulse responses, and with the ability to select which part of the spectrum is being convoluted. the results can be very interesting, though hard to predict most of the time.
The patch can save presets, which include all settings, the frequency band tables and the impulse responses.

spectral.convolution1.0.zip
(requires zexy and bsaylor externals.)

Here is a recording I made while working on it (with the addition of a pitched delay on the output)