Pooks, send it back, you'll never want to wear it. I have the Smartwool zipT, and it is formfitting.

Hey, try some of Ibex's merino tops in XL. Here are some with slightly more relaxed fit than the zipT, and two of the items are on sale right now:
http://www.ibexwear.com/F06/View_Pro...&CategoryLine=
http://www.ibexwear.com/F06/View_Pro...&CategoryLine=
http://www.ibexwear.com/F06/View_Pro...&CategoryLine=

I have their Ibex Zephyr top in persimmon, and it's a wee bit looser shape than the SWzipT.