Forge World is also doing a pre-order. Theirs is for the upcoming MkIV Outrider bike squadron.
From the update:
The Legion MkIV Outrider Squadron contains three complete resin and plastic kits, allowing this potent Fast Attack option to be added to a Space Marine Legion force or fielded as a Bike Squadron in many Codex armies. Each model has two weapon options: twin-linked bolters, or plasma guns and they are fully compatible with our range of Space Marine and Legion accessories.
These models are available to pre-order now and will be despatched from the 5th of April. Models designed by Phil Stutcinskas.