How many ballots do you need (i.e., what do you mean by "a small number")?
The reason I ask is that I have a number of folded (and in envelopes) Spectrum ballots, but they are Marin County ballot styles from Nov 7 election. They are blank and sealed in envelopes (part of test we are conducting). You would have to ask Steve Knecht if it would be appropriate to use some of these ballots for your demonstration. They are printed with a light blue color in the header and watermarks of the county logo across the page.
I've got some available but it's up to Steve Knecht and his customer as to whether I can release them.