@Flyersfan1: Thanks. I actually have both the Click and Quiet Click versions of the V60 Matias switch keyboards. I like both of them and find it difficult to choose a favorite.
Yes, unfortunately, the stock caps on the V60 Matias-switch keyboards are not the best, and it is a bit of a challenge to find replacement keycaps. However, Matias is starting to sell keycaps; this is where I got the blank black mods, and all of them worked, including all the ones with stabilizers -- even the spacebar. They should have them up on their site soon; in the meantime, you can order by sending an email to barb@matias.ca.
You can also harvest Alps-mount keycaps from vintage keyboards. Some are available with double-shot ABS and a few have dye-sub PBT. I got the dye-sub PBT alpha keys from an IBM 5140 convertible computer keyboard. Acer 6211 and 6312 keyboards also have dye-sub PBT caps, although they are not as nice as the IBM ones.
I am hoping that Matias or other companies will produce PBT keycaps, even if they aren't dye-sub. For example, for Cherry mx keyboards, Leopold makes some very nice PBT sets that are blank or with lasered legends either on the front or top.