Frank Ladd has sent a big bunch o' links to sites with ingenious methods for adapting canoes for rowing.
Top of the list is Gavin Atkin's Cinderella made by Martin Welby, who designed a pair of wooden outriggers that just about anyone can make - no stainless steel welding required.
Next, from the excellent Roughstuffrowing forum, is an admirably simple rowing seat for Rob's boat, a plastic seat secured to a box shaped to sit on the bottom of the boat.
Also at Roughstuffrowing, Ihwyllis created a simple and rather dramatic outrigger using a thick plank of wood.
This Barnegat Bay boat has a drop-in rig with outriggers made of laminated ply, something I have seen done but never dared try to make.
And finally, from the Ferwerda company in Canada, makers of traditional wood and canvas canoes, possibly the most aesthetically pleasing riggers I have ever seen.
Well Stuart, I hope that something there shows you the way forward. They certainly got me thinking. Thanks, Frank.