There are plenty around - i have a few digital plans too - pm me with your email address -will send you a list .
Also check Sarik for plans under steamboats -
Vic Smeed did a very nice clinker open launch River Queen and a half size River Princess - depends which size you need . A picture of a friends one is posted elsewhere on this site a while ago - his one runs on a LARGE Stuart Double 10 and a 3 Drum Yarrow boiler. Hull is genuine teak.
A search under Steam Boats will find the thread