I want to surprise someone with a pair of fingerless gloves that I want to knit myself (hopefully), but I don't know exactly how big his hands are xD Thanks!
There is a woman at my LYS sock class who is using Cascade Fixation for her grandaughter's socks and it's very stretchy! Lots of places sell it, here's one. http://www.onefineyarn.com/Merchant2/merchant.mvc?Store_Code=OFY&Screen=CTGY&Category_Code=CAS_FIX
Knitting something with ribbing will make a big difference, even if just a couple of 2x2 rib columns on each side.
There's also this:http://www.straw.com/cpy/yarns/Maizy-scans.html
These are all fingering weight, though. I think the stitch you use makes more of a difference in the stretch factor. It's really best you get an idea of the size of the hand you're knitting for.
Oh, I forgot about Nashua Cilantro which is a worsted weight cotton and polyester yarn. I really like it.