Here is what I know.
There was a farm auctioning off a lot of imported stock around 2009. I remember there were a lot of English Orpington, there were Cream Legbars, and probably Sussex and other English Heritage breeds but I don't remember all the specifics. The prices on one of the auction was up to like $5000 (I think this was the Cream Legbars) for imported breeding stock but was listed as not reaching the seller's reserve. The auctions were up for a long time after they closed but can't be found on-line anymore. If my memory serves me well it was Hambrick farms that was auctioning the stock. I believe the auctions were all Pre-sales for stock that was being imported but were not available to ship to the auction winners yet because Green Fire Farms told me that their was a farm that did a Large import of around 300 birds about that time who weren't able to clear the birds through customs because they got Mareks and where all destroyed.
Another imports was done by River Rock Farm in Utah. If I remember correctly they were making a trip to the UK and asked the friend they were visiting about sources for Cream Legbar. They knew a man that was breeding them and asked him about importing stock. The man have just had his flock tested and certified by a vet a few day earlier and said that he would do the import since they were with in the 30-day period of testing but that if he hand't just got his flock tested that he would not have been open to the import because it wasn't worth getting his flock tested and a vet to certify it just so someone could import stock from his flock. I am guessing they got a licence to hand carry hatching eggs but am not sure. They did however have a 4 month old cockerel and two 4 month old pullets when my wife contacted them. She was going out to Utah to visit family a few months after than and had plans to get stock from them. When my wife went out they had lost one of the pullets, hatch chicks from the other but their flock had tested positive for Mycoplasma and so they closed thier flock and would not let anything leave their farm. Rock River was one of some thing like just two farms in the country to be certified through the Heritage livestock association (organization?) and they tested for everything (much, much, much more involved than any level of NPIP program). She got the Mycoplasma from when she brought in a cuckoo Sussex sport from a neighboring farm. They were considering trying to treat hatching eggs for mycoplasma and try to clean up the their flock so they could re-open it. I am guessing that their flock didn't survive.
The Howington line was started in 2004. Is was NOT an import but rather created in the USA but crossing champion barred rock with single comb light brown leghorn. I got three hatching eggs from this before the Green Fire Farm Cream Legbar Lines were available. At that point they were autosexing but they were not cream in color, were not crested, and did not lay blue eggs. The met the English Standard for Gold Legbar at that point. I had worked out a breeding plan for introducing the blue eggs gene into this line to make my own blue egg laying Legbars. It was going to be a 5+ year breeding plan to try to create crested blue egg laying legbars from the Gold Legbar line so when the Green Fire Farm lines became available we ponied up $400 to get a few day old chicks. We only had a single hen and a single cockerel survive past the 7 months old. They were our foundation pair. We didn't work with the Howington line after we got Green Fire line birds. H&H Poultry (owner of the Howington line) sourced a Green Fire Farm cockerel to put with their Gold Legbars to finish their Cream Legbar project. They still are breeding Legbars and so you could get stock from that line. It is a mix of the Green Fire Line and American blood.
On of my sources in the UK who was well know for his Legbars and large commercial egg distribution told me that he had a meeting with Pete & Garry Organic Eggs in 2010. He wanted them to model their procution after his to offer free range organic eggs. He said they never came to an agreement and that Pete & Garry were going to import a German line of Legbars to the USA via Canada. I contacted Pete & Garry in 2012 to inquire about this and they never commented so it is unclear if they ever imported anything or not.
There were some claims around 2014 of a Canadian line of Legbars that were unrelated to the Green Fire Line. People were selling them on
Ebay. They was no legal import from Canada to the US so no information could be found on the source of this claim and the photos of the stock looked like people in Canada had carried from Green Fire Stock across the boarder ruined the line then sent it back across the boarder.
So...the only legitimate source for Legbars in the USA are the Green Fire lines. If anyone is offering anything else beware of scams.