can you sit down with your boss and have an open conversation?
It's pretty easy to get frustrated if you're not talking about it - if the pay and benefits are excellent, I don't really get why you need the validation of changing your title? Surely if you want a different title it's a different job role too?
Sounds a bit like you've already talked yourself out of the move and not sure I'd think about moving somewhere if I knew they were aiming to sell in a couple of years (unless of course there is a chance of a share of that, no point in going in, helping setting up a business for someone else to sell!)