Hi Ian!
Straight handlebars are fast becoming (already are) the de factor standard for global touring/trekking bikes. I'm just a throwback/old roadie/traditionalist, whose wrists and shoulders have a disagreement with the straight-bar position after so many years (35+) on drops, so I still prefer them. The truth is, straight handlebars do a wonderful job of shielding the brake levers from damage in rough handling or extreme touring use. Drop the bike over, and the ends of the 'bars (with or without bar-ends) hit first, sparing the more vulnerable levers. With drops, the levers are right out there, subject to damage. With bar-ends, you have nearly the same position I do when I ride the brake hoods, and bent elbows can simulate the effect of drops. It all comes down to preference.
Like the helmet issue, I really believe it is whatever works best for the individual, so it's all good. We're lucky great equipment is available to setup the bike successfully either way.
The only thing to keep in mind when ordering a Thorn (given the generous number of sizes available) is to choose the 'bars first and use that as the criteria for helping select frame size (in terms of reach/top tube length). The shorter frames are best suited for drops, while the longer ones are ideal for straight and comfort 'bars.
Yes! Be sure you have an idea which riding position you prefer, and Thorn will sort you out on the sizing. Thorn came out with a wonderful guide to actually *show* the various riding positions, so one can just point to desired positioning. For those who haven't seen it, the link is here:
http://www.sjscycles.com/thornpdf/SetUpHiRes.pdfSize, equippage, etc. are all important, but pale to insignificance compared to the real question...what color will you choose?
Ian, it is really exciting to see the "selection process" take place for you, and you've been generous to include us in the process. I have every confidence you'll get the "perfect bike" for your needs, and can't wait for the day when we see a photo of it in the Gallery. Any questions, give a shout and we'll scramble to give the best answers we can.
All the best,
Dan.