I pretty much did that. I had a 10 foot bobcat for a while a play boat and it was a hoot to paddle, and could pretty much go any where, but, it was a one person boat. Eventually I got a JPW culebra, and was able to get my son started on whitewater ( it was really easy to R-1) and was able to keep him on the water till he gained the confidence to paddle his own boat.
It took me about 8 years to finally slap a simple frame on it (from rowframe.com) and it is a blast. almost as maneuverable as the bobcat, way less time to get it on the water, and the ability to run it as a paddle rig. I do think the sabertooth will be better than the culebra as an oar rig because it is longer and will be less sensitive to fore aft balance issues.
The frameless boat will go together faster, the cat will be stiffer. I like the greater versatility, but that is just me. Having said all that, there may be a guy out east selling a relatively new hyside, oars and frame around albany NY for a pretty good deal. He was posting on NPMB. It did have a goofy slantboard seat.