Gymboree's slim sizes fit my two skinny boys well. We also have had good luck with Crazy 8 (which is owned by the same corp.). They all have internal adjustable belts, too, which makes the slims even slimmer.
Old Navy too. They make both regulars and slims with adjustable waists. Ds varies from being <i>really</i> slender to just slim, and the adjustable waists are really helpful. At times, the slims are too big, but we can adjust them in to fit him. More places are doing that, but most of Old Navy's stuff is adjustable.
oh, yeah! how could I forget gap jeans. They are what my oldest DS has the most of b/c they hold up better (he can make a whole in his knees the 2nd time he wears a pair of pants!). I wait and buy them when they run specials like BYG1F or half off the 2nd pair.
The Children's Place makes regular, slim and husky sized pants. And most of their pants have the adjustable inner elastic band too. Clothes are very well made and do not fall apart, but can be a bit spendy - Sign up for coupons.. Selection online is great!<br><br><a href="http://www.childrensplace.com/" target="_blank">http://www.childrensplace.com/</a><br><br>
Arizona brand makes a slim boys pant and husky size too. We purchased at JC Penney and the fit was perfect - no adjusting needed!<br><br>
It may depend on your child, but we've found that Children's Place slims are not very slim! We ordered a bunch, but they're uncomfortable for my ds because we have to pull the elastic on the adjustable waists so tight, and they end up all bunched up. I look at these "slims" and I can't even imagine how big the regulars must be! The slim size 6s are seriously three inches too big around the waist, which is a lot at that age! The legs also don't seem to be slim cut at all; we could easily put three legs the size of my ds's legs in each leg.<br><br>
I hate paying Gap prices for jeans, but their slims are actually slim, and the waist either fits or is only a bit too big for my ds. That makes them a lot more comfortable for him. I watch the clearance rack there and find slims occasionally, and a couple of times I've gotten them on clearance online.<br><br>
I'm going to keep watching for other ideas!