I've seen, but not purchased, a longer bbl for my 20. I like the concept of just swapping bbls for more oomph and a tad more accuracy. Glock markets that bbl (#SP07557)as a hunting bbl and has offered it for quite some time, actually, but it's just not well known. I would buy the extra bbl long before I bought another complete 10mm; having the 20 and 29 are plenty for me for such a low-use caliber. For me, it's a whole lot cheaper (and easier) to get a bbl than a whole gun. And it gives the exact safe effect.
Honestly, rather than making the 41, I don't know why they didnt' just offer a longer .45 bbl not unlike the 10mm long bbl. I suppose the market will gobble them up, though.
Since I'm factory certified armorer, I pretty much stick to OEM bbls. I'm not saying the aftermarket stuff isn't good; much of it is. I just have very limited experience with aftermarket stuff for Glocks; I find their factory parts good enough for what I want. My neighbor did have a LoneWolf 9mm to add a suppressor; it seemed like a decent made bbl.