I tracked down a good condition 2009-2010 vintage A1242 aluminium ten-keyless Apple Keyboard[1] on ebay for £54 last year for exactly that feeling. Supposedly they came with iMacs for just a year or so before they were discontinued. My first-gen Magic Trackpad fits perfectly where the numpad would be. My only complaint is I can't position the trackpad below the spacebar like on a MacBook so have to move my hands from the home row, but that's because the keyboard and trackpad both have a slant to them.
[1]: https://en.wikipedia.org/wiki/Apple_keyboards#Aluminum_w/o_N...)