Hi Frank,
Actually I have a little bit of experience in this. I was involved in getting a monument built to the Connecticut Volunteers at Vicksburg Military park. You have a lot of different avenues you could follow:
Do you know the hometown of the honoree? Perhaps a letter to the local newspaper or the mayor of the town might get some interest going. You might find someone to run a small fundraiser for you there. (Don't discount those small donations) .
The local tourist board. By placing something for tourists to visit, you will be helping to pull tourist dollars in. It would be good for them to pitch in little money and it would be good for local restaurants, hotels, petrol stations.
If you know that your honoree belonged to some kind of an organization? We were very fortunate that one of survivors of our unit was involved in the Knights of Columbus and they made a donation in his honor.
We found several relatives of people in the unit just by posting on a bunch of websites dedicated to the Civil War, Writing letters to Civil War Roundtables and a representative from our group attending local festivals and fairs with a small booth and collection jar. There must be a way to find WWII organizations that would be glad to post on their website or print a small article in their newsletter....
Hope these help. I can't wait to see the finished product.