My A4000T came with that model Sony HD drive installed with the little converter on the back and it works great. It looks like a standard drive that is still available. I could probably make the little board with Eagle or something, but I have never actually done it. Someone that has made PC boards before could probably do this in no time, and there are companies online that you just email the .brd file to.
As far as duplicating the PAL IC, for all I know this could range from simple to impossible. Again someone will know:-)
Either that, or we need a device that will replace the floppy with an SD card, or perhaps a modification to the Kickstart ROM so the machine will boot to something other than a floppy drive at DFX: