Are you guys looking for slates in the traditional sense, like a wrist flip slate and/or a ridged pocket slate, or are you talking more about a pre-printed pages that you can zip tie into your wet notes (like if you want to supply pre-printed NDL tables, gas rate every 3 meters, MOD chart, whatever).
If the latter, yeah definitely just talk to your local quick printer about doing some printing onto a thicker "synthetic". Its basically plastic paper that is tear-proof and water proof but laser-compatible. Any decent size quick printer should be able to run your PDF on their digital press onto synthetic stock. You can still cut it with scissors or a paper trimmer and punch holes in it yourself using a single-hole punch. Synthetic stock can be as cheap as $1 per page plus printing costs.