No, PipelineFX does not offer cold or hot spare licenses of Qube! for the supervisor or workers.
This is a question that has been asked by a handful of clients, but it is not common.
In the event of a hardware failure, the replacement hardware would need to have it's MAC address mapped to the Supervisor, so the difference in keeping a cold spare around and requesting a replacement license from PipelineFX would be negligible. If the plan were to keep both the hardware and Qube! Supervisor on a hot spare, then you would need to upgrade both your spare and production Supervisor together so you don't get out of sync. In the mean time, you would also need to make sure your database and assets are available to the hot spare pair of hardware/software immediately. This is not common practice and is not a frequent request from our clients, so in keeping with industry standard, we do not offer this.
Workers can be placed on any hardware, for the most part. There are very few, if any, exceptions. So, spares just aren't needed and are not a concern. For very short term license availability, we offer the option to rent worker licenses per day, per month or per year. Plus, you can use Metered Licensing to burst beyond your current capacity and only pay for what you use.