Ok, I have as requested read the FAQ and "what boot will fit" and searched for other threads from people with wide feet, and I think I've still got a question to ask the boot guys.
Here's the deal: I've been working with a bootfitter, trying to get a good fit for what appear to be wide, flat feet with a SMALL heel and lower calf. When someone measured across my foot from the bunion just below my big toe, it was 120 mm straight across, 130 mm to what's actually the widest part of my foot, which is well behind my small toe.
We started with a Technica HVL 120 (2013) in a 27.5 (106 mm last). Getting the forefoot wide enough involved heating and molding the shell in the store, then subsequently punching it out along the outside of the foot, then me boiling-and-buckling at home. He heated and stretched the liner in that area, too. We also did footbeds.
The heel, though, is apparently way, way, way too wide: I have a foam ankle wrap (around the back and under the ankle bone on each side) on the liner on each foot, augumented with an extra piece of foam on each side of the ankle (one foot) and with yet another piece of foam on the other. Heel hold and stability on the side with "only" four widths of foam around the heel is reasonable. The other one (with five), not so much, but that's a question for a separate thread.
Everything I've read here suggests that padding the liner like this is at best a temporary fix, good only until the foam breaks down. When I raised this with the guy I was working with and asked about maybe starting with a boot with a narrower heel (and maybe a lower instep?), he said that, past a certain point, you're basically screwed: you can't punch a boot out too far without distorting how the toe plate and the heel plate are aligned.
Does that make sense? If not, what kind of lower-volume, narrow-heeled boot might be stretched to fit that kind of forefoot? If it does, is there a more lasting or general fix than taping foam to the outside of the stock liner?
Thanks for any info. I've tried to provide the details that seemed like they'd be relevant, let me know if I've missed something.
Not sure whether they help, but here are pics of my feet. The left one (top pic) is the wider and (slightly) shorter, also has a protruding navicular bone you can only kind of see, for which the boot is punched out.