there were a couple projects at one point that did flexible replacement PCBs for the Advantage2 that would upgrade the board to QMK (Stapelberg?) – could use it as an excuse to update switches and keycaps?
These are separate things. You can easily replace the SmartSet controller in the KA2 with a KinT controller with QMK. The key wells and thumb clusters are connected to the controller with removable ribbon cables. The swap-out takes maybe 5 minutes.
Kinesis offered replacement flex PCB and key wells in the past, so that you could replace your switches. They don’t sell them anymore and instead you have to go through an expensive UpgradeKeyboards.com build.
don’t remember anything recently (was under the impression BastardKB had something but I can’t find anything on the website) – and it seems most people working on Dactyl variants usually end up just using the Amoeba PCBs because they’re easier to source …
They have them in Dvorak (QD). But presumably, most Advantage users are touch typists and the Advantage is programmable, so there is no real need? I use mine with blank PBT caps.
Last year I made the switch from the KA2 to a custom built keyboard (Scylla kit from BastardKB) and I have been really happy with it. Keeps the curve of the hand, has better thumb clusters (IMO), is split, and has full customization through QMK. Plus it was fun to try building my own!