I also have tried to find one to take, but could not. I agree with withnail you will probly not find one.
I have used and can reccomend this one
http://home.hetnet.nl/~f2hj.heilijgers/indexen.htm the link is on the left hand side of this site. It's a little more then the one withnail took, 250 for 2 hours, up to 20 people I think. The captin was cool and had no problems with smoking, eating and drinking on board. We even stopped to pick up some bud since we ran out.
good luck!