Go over to www.intlwaters.com . A guy over there is building one up using the new K&B .18 engine. Look at "Hydro-therapy" in there. 80 MPH is too much to expect out of that hull. One member (Glenn Quarles) in there has built a specially built 'rigger in there and is seeing 75+ MPH with a Rossi .12.
There are a lot of boats out here, most of the better ones aren't advertised in boating magazines or available through typical Hobby Shops.
The International Waters site also has plans and kits coming out for .12 'riggers. you will see a lot more appearing soon as the IMPBA has just approved as of Tuesday an increase in the displacement to .129 cu. in. so that more of the current R/C car and truck engines can now be raced in the "A" class.