Well, jags...
Given the overall fine condition of your components, you could likely transfer your...
• Bottom bracket
• Crankset/chainrings
• Pedals
• Chain (if shortened)
• Cassette
• Front derailleur
• Rear derailleur
• Stem
• Handlebars
• Brifters (brake lever/shfter combo)
• Seatpost
• Saddle
• Accessories (bike computer, GPS, tool bag, etc).
You would have to acquire...
• New brakes (calipers of some sort; your cantis won't fit)
• Either new wheels (complete) or new rims and spokes relaced on your existing hubs (and add the labor for same)
• New tires (700C instead of 26in)
• New tubes
• New rim strips
• New mudguards
• New cables/cable housing
• Probably a new headset. I've found the alloy cups will *sometimes* distort slightly on removal and then cause problems when reinstalled. Not every time and it is rare in my experience, but it happens often enough that I just sort of mentally figure on a new one even if the old headset is in good shape. If the old 'set is worn, then there's no question; I replace it as a matter of course. In the end, it is a very inexpensive way to avoid mysterious and nasty handling problems.
As someone who enjoys building wheels, I'd go that route (though spokes and rims can really add up even with free labor and reused hubs), but if I had to *pay* to have new ones built (or bought them pre-made), that tips the equation farther away from trying to transfer the parts, as AndyBG so sagely observed. As he also mentioned, all those little ancillary items add up -- tires, too; ones of good reputation aren't inexpensive. Of the things you'll need, I think it is the wheel cost that will hit you hardest after the frame. I kinda hate to see the dynohub go, 'cos it is about half what you need to keep your nifty new phone reliably charged and possibly powered as you ride; you'd need a charger and perhaps a buffer battery as well, depending on your use and requirements.
If you don't have enough spares on hand to do the swap out of available stock, then I must agree with Andy; it's going to add up -- perilously close to the cost of a complete bike. I agree with him, looking at the (to me, on this side of the Atlantic, staggering) levels of depreciation on used bikes where you are, then yes about half original price for everything is a realistic figure for the Sherpa's parts. If SJS Cycles happened to have a special price on an Audax frame or perhaps even a demo bike or one that had been turned in, then the tables tip more in your favor, but building up a frame with *new* parts is expensive, and can still be expensive even if you do a transplant of many of them.
I suppose the ideal from a cost standpoint would be to buy a complete Audax at a good price while you still had the Sherpa, then swap parts between them so the Audax was configured with your favorite components, then the Sherpa could be sold on as a nice complete bike for someone who didn't already have a particular parts spec in mind. Trouble with that is these are two bikes with essentially different missions -- a lighter weight, sprightly do-all versus a bike that's a great all-'rounder with heavy touring capability. Swapping parts between is likely to dilute the Sherpa a bit for the next buyer.
Hmm. Here's a thought: Could you swap the 700C wheels from your Raleigh into an Audax as needed, perhaps with a tire and cassette change? Yes it would be a hassle when changing bikes, but I got by doing that for awhile and it did give me the benefit of two bikes at much lower cost till I could afford (to build) a second set of wheels. As for touring on fairly light 700C wheels, I never had any problem and found running wide(r) tires on light/narrow rims made for a more touring-durable wheelset than I might have expected.
Just thinking aloud and trying for ways to make this more possible for you...
All the best,
Dan.
