Hello Kato,
The LMK04906 has an IBIS model, as do a number of other LMK devices.
If you are interested in a specific device that does not have an existing IBIS model, please let us know of your need on this forum.
In general, we don't release SPICE models for digital devices, but do on occasion when requested. I'd hesistate in releasing a SPICE model for this family of devices. These are large complicated devices which may well have convergence issues, and would take a long time to simulate in the best of circumstances.
Regards,
David
Webench Design Center