was thinking it might be possible to create a protocol for signatures where
some bounded elliptic curve parameters are in the script, allowing the
efficient verification of a broad range of elliptic curves schnorr
signatures... rather than a fixed curve

has anyone proposed this sort of thing before?

seems like it could allow higher bitness, broad hsm compatibility, and a
"decentralization and competitiveness" of security parameters for different
environments

would be useful to me, but not sure how many people care about this