Make one up, that way it will be tailored for your teams needs. It is a big undertaking so be sure to get a couple people involved. Look at each part of your team make-up and determine what areas you want covered off in the training. PSD covers such a wide range of skills you'll never effectively cover them all in one scenario so target your key points.
Do you want to work low viz, or do your guys need to work on photo/video, evidence collection skills. Do you want to set up a rescue scenario for the team where one of their members gets in trouble during the call-out? Could be a major diving emergency to something as simple as a tender taking a jammer on the shore. (they may even forget about the guy in the water!) Assuming they know that such and such a date is the training day and it starts at 0800, call em out at 0600 to test their readiness. By tailoring it to your teams needs you can maximize the effective enss for your team. With differing SOPs, what we do may not work well for your team. Ideally if you can pick the brains of other PSDs, it is always best to base a scenario on a dive call that actually happened somewhere. It adds to the de-brief to say, "Look, this is what really happened and ....."
There are a number of safety issues with this type of training that need to be covered off above a regular training day, but they can be easily managed. If this is something you are interested in floating to your team, let me know. I do this type of training on a regular basis and would be happy to provide you with any suggestions, guidance, or advice you need