Spanky,

Ok, I feel strange calling someone Spanky...

I believe what you are addressing here is not a matter of staying current, but instead what we're talking about is recency, which is a whole different animal.

Airlines want to see recency, actual hours at the controls... in the air. It is common to ask how many hours flown in the last six months, for example. And, many airlines will ask you to back out any sim time you have in your logbook which can severely decrease your time - and now suddenly you may not even meet their minimums.

If I am reading your post correctly - you are potentially looking at a sim instructor position after the transition? There really isn't anything wrong with that, except for the lack of stick-time. One of the questions I have to ask myself is, If you land a sim instructor position with an airline are you locked into that position forever or can you transition to line flying?
Some airlines separate the two, each being their own career path. Some require you to be hired as a line pilot first and then transition over to a sim instructor.

If you're talking about instructing for a school of sorts then we're back to square one with stick time.

I'm not sure this answers your question. Perhaps you can be a little more specific with what you are seeking?