Deutsche Optic has old teak grates salvaged from steamships - one is 13 x 61 inches. I don't own a TI yet, so maybe someone could answer this:
will that long one fit lengthwise across the akas? What is their center to center distance?
"...these teak grates are salvaged from ocean-liners that were built back in the glory days of Blue Riband chasing. Each grate is restored and complete, in fully usable and beautiful condition! Mind you, this is all pre-plantation teak wood… Thick, rich in color, and much harder wearing than modern teak. Use ‘em around the pool, showers, or make splendid tables or shelves. These are the real thing! "http://www.deutscheoptik.com/product_info.php?products_id=3623
Anyway, if they would fit, it might be a good source for a whachamacallit - I can't remember the term for the bench seat.
Spokane WA USA