We're not going to see any new 040 designs. The 040 chip prices are too close to 060 and the performance and compatibility in AmigaOS is much lower than 060. Plus with a voltage regulator in place an 040 board could take an 060 chip.
The problem I envisage with looking for recycled 040/060 chips is the equipment it's probably too late? Everything with them in was scrapped many years ago?