I contributed to a local center in CT. ( the Connecticut Austim Resource Spectrum Center) We found out about the place because of a few charity events (walk a thons, etc) that the center runs that we have participated in. I unfortunately dont have any pictures of what we used, but I can describe it as best as possible. I used a small piece of letter stationary (not an 8.5x11
.smaller). I lucked out because my bridesmaids wore black (nighttime wedding) and the paper had a really pretty black boarder on one side of it. I dont remember the exact words I had on it but I have a copy of it at home if you would like me to email it to you or I can post it here later tonight. (Or, if I have an extra copy I can send it to you in the regular mail. just let me know)
I had them placed flat on the bread and butter plate at the reception. Very simply done, but because the paper was really pretty it didnt take away from it at all. I know people who have done note cards, scrolls, etc. I was able to print them off myself, using a fancy font, so the cost was minimal. We donated $500 for a wedding of 240 people. I think that the total I spent on the paper was around $40-$50. (It works out to $2.30 per person and not a ton of work either). I had to get boxed sets, but I am still using the envelopes now, and I have been married for almost 2 years.
As for people not liking the idea
most people I know were so glad that they didnt have a little trinket to take home. People stopped me during the reception to say what a nice, thoughtful idea it was. (Especially after seeing the parents of the autistic children crying when they read them)
Let me know if you want any more information, I will be glad to help