That model, but without the numpad, is still my favorite keyboard (the A1242). I've tried mechanical keyboards for fun, but I keep coming back to this one for the low profile. It was only sold for a year or so before the wireless model replaced it, and it's hard to find them now. What I did was to look for used iMacs from 2010, see which ones have the A1242, then ask the seller to only sell me the keyboard. Based on…
People seem to have forgotten eBay exists -- the A1242/3 is still readily available on there. I cringe a little seeing all this affection for the A1243, after having seen scads of them go into the scrap heap at my local nonprofit electronics recycler.
+1 for eBay, anyway. I've made an exception for my M1 MacBook, but generally I try to buy everything used.