I saw some videos and a description of using a 5 gallon bucket to make biodiesel. Space wise this sounds interesting to me because i don't have the room for a full setup at this time. Is it possible to attach a small drain to a 10 or 15 gallon drum to be able to relieve the glycerin and wash water from the bottom even if it does not come with one? Has anyone else tried this?

yep. Check out this link.

http://www.biodieselcommunity.org/standpipewashtank/

The problem with a 15 gallon processor is that it takes the same amount of time to make 15 gallons as it does to make 40 gallons with a slightly larger processor. You end up spending a lot of time making a small amount of fuel. My current processor is based on a 55 gallon steel drum and takes up 4 square feet of space. That includes processor , wash tank and storage tank.