That I don't think is unusual at all. I'm a native English speaker and I frequently use that form to place emphasis on the object. For example, consider this exchange:
- "We accept $20 bills"
- "I only have a $100 bill"
- "That we do not accept"
The comma is not grammatically correct, though it seems yours is a pacing comma (often used in slogans, but not recommended for technical writing.)