I have heard of this before, but the term 'ugly' was not used. Cleopatra may have been short and fat, but that was pretty common for women of her age back then, who could afford to eat well.
Women are usually shorter than men.
Had she been tall, the Romans would likely have classed her as an 'Amazon' queen, rather than a 'beautiful' one. The curves were considered a sign of wealth. It wasn't as if she was huge to the point of immobility. She was obviously firm and agile enough to impress Roman rulers in a time when there was no shortage of 'disposable' women and boys, if that's what they wanted. Also, she had alot more going for her than her looks.