They dun and R-U-N-N-O-F-T
Around here its the same...50 cal is definitely the most common front stuffer out there. There are just about as many .45 cal as there are .54 cal, I assume its because .45 cal is the smallest allowed for whitetail deer. We rarely see anything above .54 cal, if we do its a modern remake of an old military item used for reenactments.
I make every attempt to not miss the local ECA show here in Effingham because one of the largest dealers doesn't like muzzleloaders and it is reflected in the prices. I purchased a T/C Grey Hawk for $75 and passed on a CVA Mountain Rifle simply because I wasn't certain what model it was or its country of origin, but let me assure you it was priced right.
We are starting to see some custom and semi-custom stuff around here. I have thought about something like rfd had done, but couldn't decide between Rayl or Hoyt. I did buy a barrel from Green Mountain and would offer that up as an option to you and the fine folks here on the forum, but percussion breech plugs are non existent. I have tried Pecatonica, Track of the Wolf and The Gun Works...they all have them on order, but no expectation right away.