Found you via your participating in the first R2AK. I made the mistake of showing some of your FB videos & pictures to my 7yr old. She is over 4' tall and now incredibly jealous that her little brothers may get a boat that she can't fit in. I might have to scale this up. That or just borrow the SISA club's Laser for her to learn on (laser too big for a 7yr old? may be I need to check out a sunfish?). Anway.... great work on these. More videos = my kids bugging me more and more about getting this done for them. :-)
I'm glad to hear your kids are getting inspired to get out sailing. An Optimist is a pretty good boat for a seven year old. Or, as you say, you could simply scale up a Bumblebee. An enlarged Bumblebee would probably get about the same performance as an Optimist. Have fun with that!