Fun to see this somewhat old tread come alive again. It made me realize that I forgot to follow up on my promised feedback regarding how I liked the Mellotron 4000D Mini I bought more than a year ago. So here it comes, I love it! It sounds realistic to my ears, and it sits really well in he mix and cuts through just the way it is supposed to. It is warm and alive and has no digital harshness that I can hear, but I can't tell if it sounds just like the original as I haven't had a chance to compare it with the real thing.
It is kind of sad that the extra sound banks are way too expensive, but you will do fine with what's in it if you are looking for the classic Mellotron sounds used by many 70's bands.
If it is worth the money? Hardly, but then again, what is? The good thing is that it seems like they are holding their value in the used instrument market pretty well, and they still sell for at least the same as I paid for mine a year agao. So if I should decide to sell and get something else I would be fine.
Regarding the "supplier" linked to above, that is the manufacturers web site. http://www.mellotron.com