i have the gigasampler version of the mellotron its got this 1 really cool sound.
maybe you should start a library of your omni. i have a small sample collection of my korg delta , kinda simaler synths maybe we could do some tradeing if you have any use for samples
you should look into tassman or reactor , their both makes of those virtual modulars you were talking about in the other thread you can build a synth from the inside out . add one component at a time, you could easily recreate an omni with eather one of them , as long as you know the correct number of oscillators and voices and add all the improvements you wish it had of course it wont look like an omni