I wouldn't be optimistic either. This sounds very typical of sellers who take people's money and then don't ship - excuses or promises of shipping coupled with poor/nonexistant communication. I think you've been very fair and tolerant. This kind of unfortunate scenario is why there is Buyer Protection on PayPal.

I hope you consider posting lights about this seller. If by some good chance you do get your model even cautionary yellows. I know I would be upset having gone through this if it was me