This is a good point, but if one is looking for a "ready made" solution (which the OP seems to be inferring) then making a stainless deflector might be more than he wants to mess with... course it's not hard; just get an appropriately sized piece of stainless steel in a square or round shape, cut the corners off the square part (to eliminate the risk of snagging or poking clothes and body parts while working at or transporting the pad, hooking up the rocket, etc.) and then drilling a hole to go over the launch rod.
At 59 cents a piece, though, the work is done for you with a box cover... cheap enough to replace once a year... ignitors probably cost more than that! BUT, if you're looking for a more permanent solution, then yeah a stainless deflector is the way to go... or glue a tile to a box cover, which would be a pretty easy thing to do, compared with cutting corners off a stainless piece and drilling it to fit over a rod...
By the way, when it comes to rods, the OP mentioned "obtaining them from the local big box hardware store" (or to that effect) and I would caution the OP NOT to buy the mild steel rods available at the local stores... they will RAPIDLY rust when exposed to the hot, corrosive compounds present in rocket exhaust, and a rusty rod will give you no end of problems... While "servicing" rods is certainly an option, by sanding off rust, either with sandpaper or a scotch-brite pad, and attempting to minimize and prevent rust by applying various materials like WD-40, wax, etc... it's basically a losing battle.
A FAR better choice is to go to your local Fastenal store (or other industrial supply) and get a STAINLESS STEEL launch rod. I got a stainless assortment of rods, 1/8, 3/16, and 1/4 rods, in 3, 5, and 6 foot lengths.
Stainless rods won't corrode and are easier to clean than mild steel rods, which is all that's available from the local indoor lumberyard type stores.
Best of luck! OL JR