I agree with Roetzel that the slimmer a shirt's fit is, the shorter it may be. As a result a slim fitting dress shirt wil not necessarily be too long to wear untucked. Also, my formal trousers have a substantially higher rise than my casual jeans due to which I don't have problems with the shirts pulling out when tucked in when worn formally.
The more formal the shirt the harder it is to pull off though imo.
The untucked shirt, for me, really is something for the warmer months of the year.
This seems about right, lengthwise.
Examples (Click to show)
Edited by Crat - 3/10/13 at 12:28am