As such I would recommend helping to vote up that idea to raise the awareness for this type of feature with our Product team.
or if not does anyone know if there is a custom one that anyone has built?
For this I would recommend reaching out to the Jive Developers space here on the Jive Community as there you will be able to collaborate with other developers on potential custom tiles they have created.
Thanks Jesse, I will go vote this idea up, and post the question about a custom calendar tile in the developer space. Thanks for your reply.