Looking for a fitted merino T-shirt

Maybe the closest maker of an Arcteryx-type fit would be….

Arcteryx?

The Icebreaker Bodyfit line – several fabric weights and shirt styles…

I have Smartwool, Icebreaker, and Stoic merino pieces. All sport a rather trim cut. Smartwool may have the most length, since you mentioned that being important, but I'm not "tall" so can't say if it'd work for you.

The Ibex stuff is very form fitting for me. I would recommend their t-shirt and woolies base layer. For me the smartwool stuff is very baggy in comparison (5'8" 155lb size M).

Fwiw, I have two Icebreaker lightweight t-shirts; a superfine ultralight 140 wt and a gt velocity ss crewe 150 wt (non-zip version). You can tell the 140 is more sheer, but has has been significantly less durable than the gt. The collar is fraying and rolling after limited use. Not so happy with the 140.

On the other hand, I run in the gt quite a bit and it is holding up very well. Definitely a sport-fit with multi-panel athletic cut. The back and underarm areas are vented/mesh-like. Fasted drying merino shirt I have.

edit: I'm 6'1'' have a large and the length is fine as it has a moderate drop tail.

Icebreaker 140 –

Any fine garmet: Light, sheer, or durable – pick two.

140 is Very light. I'm getting holes in the legs simply from putting it on and taking it off. I bought it as a very light weight PJ bottom, and it has served very well for about 3 years.

But I'd recommend a heavier weight for more durability.

You could try something made for cyclists, like this from Hincapie:

http://www.hincapie.com/products/menswear/base_layers/?product=30200M&type=1

The company is fine, but I have no experience with the product itself.

IO BIO euro tee.

Icebreaker starts at 150gm2 now, and the body fit is more fitted.

Their GT is fitted, longer in the body and sleeves and has a better fabric option for running, XC skiing and winter bike commuting

Ibex woolies is very trim fitting but is ribbed-woven, so stretchy and non-constricting… comfy! If you're between sizes I'd go up one… great shirt.

I have had a lot of success with MEC's brand:

http://www.mec.ca/Products/product_detail.jsp?PRODUCT%3C%3Eprd_id=845524442633260&FOLDER%3C%3Efolder_id=2534374302888494

Slim, snug fit. Awesome price too.

I'm 5'11" 155lb. and I really like the Stoic merino Ts in Medium. Plenty of length to stay tucked in, form-fitting but not tight, and really soft. You can find pretty great deals on them on SAC from time to time too.

another vote for MEC if you live in canada … if it wears apart, just take it back for premature implosion