I didn't consider those 2 portaging options good either and had heard you couldn't use the ordinary clamp-on yoke, which I suppose is why they didn't recommend it.

I like Solus' idea, but . . .  from Placid website:

I don't see any screws or bolts holding parts in.  How do you attach your footpegs, seats and other parts?

Composites and drill holes don't mix.  When holes are drilled through a hull it: 1) creates a hole in a perfectly good boat (bad idea); and, 2) creates a stress riser that will inevitably begin to crack as the part bolted through the hull flexes and the bolt "works" the composite.  There are plenty of old composite boats out there with drilled and bolted outfitting to attest to this.  We use a special marine adhesive to hold all of our outfitting in the boat.  It keeps the lines clean and prevents stress cracks caused by hull flex at hole locations.  It also allows us to put in custom attachment points for gear at customer specified locations.  Our seats are also bonded in rather than sitting on top of the inner laminate.  When a plastic seat sits on top of laminate, sand WILL eventually get between the two and it WILL act as sandpaper.

From this I'd be concerned that drilling holes in it could impact the warranty.