Alas it would seem that for the avid DIY tweaker the only (seemingly) in production solution these days is the Harmony.

I was looking for a replacement for my aged Xsight Touch (One For All version), and until I was fortunate to find a brand new replacement (they're as rare as hens teeth theses days), I too was reluctantly considering the Harmony. (I also briefly flirted with the idea of one of these, until I discovered it wasn't quite as "budget-friendly" as first seemed.)

Anyway, if you're interested, Linus (/videos" target="_blank">Linus Tech Tips) has done a ?list=UUXuqSBlHAE6Xw-yeJA0Tunw" target="_blank">video review of the Harmony.