Not saying it's easy but ribosomal synthesis of consecutive non-canonical amino acids has been achieved by some groups (https://www.cell.com/cell-chemical-biology/fulltext/S2451-94..., https://pubs.acs.org/doi/10.1021/jacs.8b07247), and many of these peptides are extremely short. Figure 5 of this manuscript describes successful applications of this for hit identification often in the context of massive peptide library screens, https://pubs.acs.org/doi/10.1021/acs.accounts.1c00391