Purism are developing Pureboot, complete secured boot process, for their devices. I am not sure how well it works with Qubes OS, but I also hope to use it some day. There is a discussion on their forums about it, but it did not progress very far yet.
Upd: Here, they say it works fine already: Librem V4, Qubes, Heads and Librem Key - Librem Key - Purism community.
Upd2: Discussion of the Purism company was shifted to a separate topic: Discussion on Purism.