Always been a fan of bullpups. Just not buddy bottle designs (ugly).
I own the HW100 bullpup. Standard size (carbine is too short and a poor shot count). It's a tad on the heavy side but the best out there in my opinion - that's if you can afford one at circa £1200+ a pop.
I also own the Stoeger XM1 of which you speak and can vouch for that without reservation. Light, accurate and very comfortable in the shoulder.
Bullpups were something of a bespoke design with fairly limited availabilty of choice a few years back. These days, it seems virtually every airgun manufacturer has one or more to choose from. Good luck with your choice.
"Fat, drunk and stupid is no way to go through life son" Dean Wormer.