The only suggestion I have for you is what I've seen elsewhere. One company I worked at would do this every year. They would have volunteers 'selling' plain blocks. Had permanent pens available for the donor to write what they chose for a 'in memory of' quilt. They had a similar set up for a 'survivor' quilt. The following year during the fund drive, the previous year's blocks had been made into a quilt and displayed. Not sure if it was ever raffled or not, but that might be an option for you after the fact.