Unfortunately, no. The Calendar report is just that - a report - and builds its' displayed information based on the records from a table. Without the entry, there's nothing to display.
The way that I do this is to create a Checkbox field that identifies the entry as a Holiday and then use the Color Coding options within the report to color any record with that field selected a specific color that will be easily identifiable to all the users. It's not exactly what you're looking for, but it's a simple solution that works well for my clients.
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Blake Harrison
bharrison@datablender.io
DataBlender - Quick Base Solution Provider
Atlanta GA
404.800.1702 /
http://datablender.io/------------------------------