I've been trying to find this out myself; from what I've gathered so far, House of Dankness, The Green Solution, The Farm, Medicine Man, and Kind Love (there's more, but I felt I found enough) sell seeds. As far as knowing if they are carrying local (CO) stains... what I know off what I recall is The Bank is a CO breeder and is what's sold from Kind Love and Medicine Man, along with a few other dispensaries I found out. The Farm is in Boulder, and hosts their own genetics in their seeds - from what I've heard, they're well worth the drive up to get [from what I've heard flower-wise]. House of Dankness features Rare Dankness genetics, which I believe are from Europe - but they've got a branch here or something... really great bud though! And I dislike them personally, as far as [flower] quality goes, though maybe they've improved since, but Green Solution also offers their line of seeds, and are CO based. I know of 303 Seeds and TH.Seeds, CO based breeders but you'd have to look up more on them since idk Unfortunately I have no experience with any of them seed-wise - I've got clones from Kind Love that came out nice (3 flowering currently) if that helps sway your opinion. I'm gonna try getting some seeds from overseas - but I wish you luck and hope I was able to help some. Peace.