A "four-season" hammock tarp (that is, with one that has doors to close off the ends) will definitely provide you with an enclosed shelter on those rare occasions that you have to go to ground. The Superfly (by Warbonnet Outdoors), Bullfrog (by Wilderness Logics), Cuben Standard With Doors (by Hammock Gear), Hammock Tarp With Doors (by Zpacks), and JRB 11x10 Tarp (by Jacks'R'Better) are all good examples of this. There're more out there; it may be worth a little investigation (all of these are just off of the top of my head).
Coupled with a groundsheet (my poncho doubles for this, if ever needed), one of these tarps and your hammock used as a bug bivvy (if needed) will work just fine with your trekking poles as a shelter option. It won't be quite as easy to pitch as a purpose-designed tent, but that's what you get multi-using gear.
Hope it helps!