Sort of an older post here, so hopefully this bump isn't an issue, but I recently went on a 10+ hour deep dive into Xeno costumes for this exact reason and thought I'd share my findings after stumbling across this thread!
I actually reached out to Monster Room the other day and got a response on the status of the kit. Turns out, Monster Room may make another line of costumes in the future. For now, the cost of producing them is too high to be sustainable. But if the prices for materials ever go down, you might want to keep an eye out for that. Apparently there was another guy whose name escapes my memory, but that's on me for being 10 years late to the party, and from the sound of it he isn't making them anymore. Big bummer, but who knows; maybe someone new will come around!
Unfortunately, your options are a bit limited in todays day and age; mostly due to a lack of makers, rather than interest. That being said, there are a few places out there that might take customs for latex Xenomorph masks if you reach out. Firstly, I'd reach out to places like ImmortalMasks, TheBasementFX and other smaller costume studios and see if they'd be interested. Make sure you inquire about any Copyright policies; a few of them don't take licensed customs.
You can also purchase this Xeno from Horrordome that's... well, it's a costume. But the pictures don't look too great, so be warned.
https://www.thehorrordome.com/products/ ... en-costumeSulacolabs is also an option, as the person above listed, but since you mentioned they're too stylized (and I agree), I wouldn't focus on them too much.
YourProps.com is a VERY old site that's pretty much a relic in and of itself, but there are a few people on there who might be selling their costumes or props on there. There was one Xeno costume from Monsterroom being sold on there for 3.8k, though the listing was years old, and the suit had been sold almost a decade ago. Still, might be worth checking out!
In my opinion, at the moment, the best option is to attempt to make your own. It sounds scary at first (and it is!) but I'd wager its a bit cheaper than scrounging around for strange and obscure listing sites that might hold some hidden gem within. Trust me, I've been doing it for hours now, and while I've found some awesome indie costume sites selling grade-a latex masks (snagged myself a pumpkin just now too, though sadly no Xeno), any potential Xenomorph costume you might find is almost 4,000+ USD or horribly made.
Now, allegedly, there are fursuit makers out there who might take the project on. I know almost nothing about them or their policies regarding more replica-quality suits as I don't tend to be in those circles, but there might be someone who'd make you a Xeno. Hopefully one that doesn't involve foam and fur. But it's an option for the more adventurous buyers looking to invest in a bigger project that may yield good results!
The last option I found was finding a 3D printing commissioner who will print you a life-sized Xeno head, which you can apply to a costume. I reached out to a few, but haven't had much luck in terms of responses. That being said, there's an awesome 3D render of a Warrior Xeno out there for purchase that'd make a GREAT helmet if anyone manages to pull it off and make it.
If your friend happens to be like me and is maybe interested in starting a latex Xeno build, here's a link to a few awesome (albiet pricey) starter kits you can do at home.
https://www.monstermakers.com/halloween ... king-kits/If I find anything else, I'll update this thread! For now, though, I hope you can find something. I know the struggle; it's been a rocky journey, trying to find anything or anyone willing to make or sell a costume.