I would like to follow up when cold minting will be implemented? There are many coins going onto Ledger wallets and it would be great to be able to stake from a Ledger. PPC will probably set the tone in this regard.
Cold minting is planned for version 0.7 (~Q3 2018 according to the
roadmap).
"Cold minting" does, however, not mean that you can mint
only with an "offline" device. Additionally you must own another wallet which is (ideally permanently) online to mint from there, but you do not need to expose your coins held in cold storage to attacks while you mint. You would sign the "connection" between both wallets/keys in advance, proving this way you own the coins in storage and are authorized to mint with them.
Regarding the implementation,
this path is being envisioned.