I asked around a bit in Delft. Seems no documented in-flight tests have been done, at least I couldn't get hold of them. Surprising given how simple that'd really be, though a respirator might be advisable...

Problem of course is that in wind tunnels we don't have seems, nor are levels of ambient turbulence anywhere as low as in the atmosphere.

I guess Britton is referring to wind tunnels tests like these performed in Delft?
http://www.dropbox.com/s/354b4wpodglrw7j/Untitled.jpg

There it's just the effect of the wing/fuselage intersection that pushes the transition point forward.

What I'm wondering about is whether flow over the canopy looks anything like the above test, or we basically have a mostly turbulent canopy, with turbulent wedges originating from all over the canopy seam.

Because if that's the case, a fully flush canopy (that by definition would have to slide fwd for ingress) would cause a major drag reduction. Something like the MOBA:
http://www.dropbox.com/s/vozyc6qby8x...bafullview.jpg