I think the only Italian Quintana disc available is one of those discs that wasn't available from online stores. Well, I think it was possible to buy it directly from the company that released it but I'm not sure if that was only for Italy. Fabbri is/was the company, not sure if their discs were part of magazines or what the deal was.
Another similar company is H&W (Hobby and Work?) which has released several dozens of discs but these weren't available at online stores either and from my experience are very rare at Ebay as well... and once there is one it went so high prices that I had to give up. The quality on the discs isn't really good usually but they have several of movies released that doesn't have any other releases. And this includes other genres besides spaghetti westerns. I bought Dallamano's Si può essere più bastardi dell'ispettore Cliff? for around 30euros or something. ;D
At least one of Mauri's Holy Ghosts was available, then one Steffen movie I can't remember the title for, Garko's Holy Ghost was also maybe uncut (as the spanish disc and the fan disc made from it is missing lots of minutes), and some others which I can't remember now... Oh yeah, Fabbri released Giarrettiera Colt in very good looking disc.
Then there is a company called Quinto Pinto or something like that, they have released at least Gatling Gun and maybe some others, but the only place I remember seeing their discs is Kultvideo and Ebay.
Kultvideo has had some of these discs available at some point.