I don;t understand the suggestions about sabbaticals. A sabbatical is not a 12-month vacation, where you can do whatever you want. At my school, at any rate, sabbaticals are granted to do specific research or writing or whatever--not to take up another job entirely. WE also have to sign something committing to return to the school at the end of the sabbatical. It's not the same as an unpaid leave of absence.
The OP sounds like he would like to work in a far more establish research lab, so as to brush up on his research credentials (in his field), this seems like a perfectly reasonable use of a sabbatical year, particularly for a SLAC professor who has limited lab resources to pursue a high profile research program.
Also, most sabbaticals don't pay your entire salary, so it's common to undertake some form of related employment to supplement the sabbatical payments.