My plates are 29 feet in length, not un-doable, but somewhat daunting to work with as I'm primarily a one man operation with the exception of the raising (when I get to that point).
As to the mechanical behavior of the interrupted plates, I'm uncomfortable with this given the application. I am an engineer by day, and though I don't design timber frames I do have an understanding of continuous beam systems, and I just can't get behind interrupted plates for a load bearing application like this without some secondary support mechanism such as a truss or the corbelled bracketing from the Asian traditions. I'm sure it's done successfully, but the loads we design for aren't always necessarily seen and I'm not going to make a science experiment out of my barn.
I've read that scarfs can attain 25 - 30% of the beams original strength characteristics, but I haven't ready a whole lot on the testing done to support that. I'm sure someone has done it, but I would like to see full scale, or even small scale testing of traditional scarf joints at skewed angles of attack to mimic the vertical load and thrust combinations that they really have to support. I can place my scarf where the beam is at equilibrium under the maximum loading, but as load cases change, so does this location, and understanding the relative capacity of these joints, as it changes across their profile would be crucial in properly engineering their locations.
I've eaten goat once, it was much better than I expected, given the critter's temperament.