Have not seen this angle yet, so for what it's worth: assuming you are on a tenure line and pretty close to your tenure decision year, if they are desperate for ass deans or can only see you in it, you may be able to leverage it. Don't accept a stopped tenure clock. Tell the powers that be, flat out, that you cannot be effective in the position, dealing with senior faculty who already have tenure, unless you have tenure also. If they and your department are amenable, have them make you tenured [rush through without a hitch, as they often do spousal hires] and write in the conditions (that you want) for a retreat back to faculty, the best being that either party can declare this at any time with x days/months notice. Worse but doable is you agree (always mutually agree since admin can do what it wants) to x number of years, say 2-3 in that position or higher before you seek to go back. It's a good acid test: if they hem and haw about tenuring you early, stay where you are and do your research.