Andrew and Tom,
Here are some sources for the LM1881 I found at places I visit often.
Anchor Electronics in Santa Clara, CA,
LM1881 VIDEO SYNC SEPARATOR 8-PIN DIP $4.15
Advanced Component Electronics (ACE) in San Jose, CA,
LM1881N (qty in stock = 112), call them to get price.
Hope these are of use for the VDP project
Best regards,
Rick