I'm no expert but I don't think there's a way to use the leverage of them desperately needing you sustainably. If you plan to leave in the next year or so then

I'm no expert but I don't think there's a way to use the leverage of them desperately needing you sustainably. If you plan to leave in the next year or so then just hit them for the best sounding job title and the most money you can. But if you do anything to instill resentment then your days there will be numbered. Personally though I see the opportunity to do the work and define your own career within the company as the biggest opportunity here. If you like what they're doing, figure out what you want in terms of role and responsibility and ask for it. Tell them you want to be the chief of this or the director of that - not just the title but the responsibility too. If they say no, do the work anyway. When they see your level of ability and commitment they'll probably start to worry that you'll seek the role you want elsewhere, and so they'll give it to you.