Although modern and "relaxed" fits have gotten entirely out-of-hand as of late (often leaving inches of fabric billowing around my legs), I have the opposite problem a lot of times when trying on pants that seem like they should fit me.
In short, I have thunder thighs.
Okay, so I'm certainly no Alberto Contador, but more often than not, pairs of pants in my usual sizing (34x34 or 34x36) that were made in the mid 80s (or so) and before often look like they were painted on my legs when I put them on.
For your sake, I'll spare you the visuals. For reference though, I'll call forth these very cool gray pinstripe Levi's jeans from what I'm guessing are the early to mid 80s or so.
Like the kick-ass cords in this post, the pictured Levis were only $1, so I didn't even bother trying them on at the thrift store before making my purchase. I had the same problem with these, though, that I had with the aforementioned corduroys, as it looked like my legs (especially my thighs) had been vacuum-sealed when I put in the work of slipping them on. Actually, "slipping" is probably the wrong term, as I nearly needed outside assistance getting them off again.
I ran into the same problem in recently buying some vintage madras pants off ebay. The waist fit great, the length was just about right, but the legs were nearly as tight as the lycra I wear when I'm actually doing long distance rides.
Damn, did I just admit that I sometimes wear lycra?