We recently automated our billing infrastructure, and I was tasked with creation of PDF invoices and usage summaries for our customers. After the customary scouring the web for good looking templates, and making a mediocre attempt at one, Ninja suggested I just copy the quickbooks template and craft the html myself.
This template is dompdf compatible and produces good looking invoices. Feel free to play around with it and use it for your own purposes.
May the source be with you here
It also has a sample invoice for you to take a look at. Some accompanying code to generate the invoice using dompdf is also present.