Eric Lidemann's Synful(synful.com) has to have a one second delay(DFE) in current sequencers because currently there is no way for a plugin (VST, DXi, AU, etc) to interrogate a host sequencer about the future of a sequence. He claims this ability could be added without too much work to the host sequencer.
I'm getting more interested in this technology after comparing it's ease of use and low power requirements to sampling based expressive instruments. It isn't as mature a technology as sampling but I think he's on the right track. You can listen to some really impressive sampling demos but trying to do it yourself can be a pretty convoluted and frustrating experience from what I have read in user's posts.
He has recently added a pretty ambitious future products list on his site.
Synful Jazz Jazz instruments with sounds of different players, styles, and historical periods (saxes, trumpets, trombones, bass, etc).
Synful Rock Pop/funk/rock instruments -- especially electric guitars and basses.
Synful World Expressive wind and string instruments from around the world -- India, Indonesia, China, Japan, Africa, etc.
Synful Fiction A software program for creating and experimenting with new fictional instruments. Synful's RPM technology is uniquely suited to exploring, morphing, and transforming instrumental sounds. This product will allow musicians and composers to explore this potential through various techniques: blending and modifying existing instruments and inventing new instruments.
I thought you might want to check it out and see if this delay feature is a doable request.
Happy Holidays!