Seamless IBC <> Rollup composability is already here.

"IBC handles transfers between the sequencing layer and external IBC-enabled chains, while the Astria bridging protocol handles transfers between the sequencing layer and its rollups.

Because they’re composable, an incoming IBC (ICS20) transfer can be combined with a rollup deposit in a single transaction, and similarly, a rollup withdrawal can be combined with an outgoing ICS20 transfer.

This allows any Astria rollups to access any IBC asset."