After a couple of years talking about it, a used tandem showed up in my garage last week. I plan on riding with my 10 year old (wife doesn't want much to do with the bikes). It's a KHS Sport and should fit the bill nicely. Depending on spring training, I told him I'd take him on RAGBRAI with me this year, the "G" rated one! All I need is to find a set of crank shorteners and I think it should fit him just fine.
ps been lurking for quite sometime now and have gained serveral ideas from these forums, thanks again!