Dia,
I obtained my (full scale approx 53in LWL) plans from Port of Echuca Shop, they offer plans
of P.S Pevensey & P.S Alexanda Abuthnot, BUT due to lack of interest !!
they only have plastic coated SMALL versions ( A3 I think ) for framing purposes.
( I was VERY lucky to be able to obtain my copies last year )
Also try B2 Model Marine (site) as they offer numerous plans at various scales
As far as Float-a-boat goes , Adrian Brewer draws a very nice set of plans indeed
and he is a well respected (worldwide) designer of MODEL RACING YACHTS.
I've seen a set of (one) of his paddleboat plans recently and they were really good.
P.S You cant go past a Aussie SideWheel Paddler, easy to make, perform well
AND you can be "rough around the edges" , because the fullsized ones are also !!
Cheers,
Brett