Would it be possible to pull the reverb algorithm from a VSTi/Reaktor Ensemble and make a new VST/AU?
I'm really liking to the reverb that comes from these few VSTi's that I've found.
http://bedroomproducersblog.com/2011/12/27/thebox-free-reaktor-ensemble-released-by-need-a-name/
http://www.needanamemusic.com/site/?page_id=138
the first link is just SpaceMaster Deluxe, you can pull that from the Reaktor User Library and use it as an effect with Reaktor as a shell.
The second ones seem to be Synthedit and the reverb sounds like a Freeverb implementation to me (bad).