Hey Neil, welcome to the forum
Glad your loking into getting a Triumph of any kind.
I can't help you concerning the forward foot controls but iffen they're out there then somebody here will know about it. As far as I know there is no Kit and I don't recall the topix of interchangeability with SM BA ever being brooched.
One option that is out there is the "Modre peg lowering Kit". He's on this forum and several people here have gotten these and seem quite happy with them. They lower the pegs by 2". Hiway bar for the Bonnie are out there. They don't have intergrated controls of course.
I know you said "insist", but bere with me a bit.
I'm 44 weigh 280lbs and stand 6'3". I'm pretty banged up but have no issues with the Bonnie.
The peg to seat height is plenty for me and if I wanted I could even go with rearsets. My knees and hips really like the neutral peg placement and don't bother me at all after a long ride.
That's just me.
If you get a Bonnie I would suggest that you give it a good honest try with the stock pegs. It might be that you just need some time to get the riding muscles loosened up a bit. It will also give you some time to explore your options.
Try to get a test ride. They are roomier than they look.
I used this site's seach feature (upper right) for you.
search query was "forward foot controls" in the "Twin Talk" with the "child forums (sub forums)" boxed checked.
results are here
http://www.triumphrat.net/search.php?searchid=388402
This result was a direct match
http://www.triumphrat.net/twins-tech...+foot+controls
peace
welcome back to the fold