I get mine just loose enough that I could wear a sweater underneath without suffocating.

In general you shouldn't be able to grab a handfull of leather while wearing the suit.  If you push on the armor at the shoulders and elbows it should not be able to move more than an inch or two in any direction (key impact areas, you want the armor ot stay put).  None of it should be "baggy" at all.  It should generally be "t-shirt" tight all around...I think that's a good way to describe it.

5ft6, 125lbs. I wear a 36 chest suit jacket, 29 waist, 30 inseam. I feel your pain but you can find stuff that fits better. Some of the euro stuff is cut smaller, like my alpinestars stuff has really small sizes. thats why I was looking into custom 1-pc suits (and why I'm ecstatic about winning the Kushitani suit!)...

Keep on the lookout for stuff that fits because if its loose like that it wont protect you as well as properly fitting stuff.

Yeah Pablo. I wish I could try some AStar stuff on before I had to buy it, but I don't think there is a place that sells it around here. The Teknic stuff is cut pretty slim as it is, but I just tried the jacket on and it IS too big. I never realized that before. So leathers should be fairly freakin' snug, right?

Yeah they shouldn't be loose at all.

you can get a custom fitted suit for under $700 from syed leathers (highly recommended). save up. or just keep trying stuff on when you see it (like when the int'l moto show was around). In our sizes stores dont usually carry much in those sizes anyway...look for extra small or better yet look for sizes that are numerical (sm is a larger range than say my 36 jacket). Joe Rocket fits my like its 10 sizes too big, even though its a small...

even in this pic you can see how my upper arm bunches up from poor fit. Better than your fit though because the armor is where its supposed to be and doesnt move around much.

My jacket is a bit loose when I don't have the 10 inches of waterproof/super heated/good for any bad weather liner in it. Unfortunately, I had to buy a slightly larger jacket since I have a fractured elbow with a little bit of bone still in it. I tried on some very well fitted leathers and such, but they put enough pressure on my elbow that I would almost scream out in pain (actually brought tears to my eyes  ).
So I figure I can just wear maybe a sweatshirt of something to keep the armor where it needs to be, and not be too hot in San Diego weather.

I'm another guy who had problems finding leathers.  I am 5'7", about 145 pounds, light upper body build.  I found a great suit, skin tight, well constructed and padded.  It's by a small company that cut me a great deal.
http://www.motogearusa.com/products.php#product01
They make an extra small!!!  Fits great, feels great and has a lot of perforated leather for good breathing ability...

Problem with an extra small for me is that usually sleeves and torso are WAY too short, i.e. only coming up to my mid forarm, ot just not fitting right. I'm going to hit the gm and see if I can't work out some of my issues that way, but I think I'm going to end up going the custom route in order to getting something that fits properly. That's a lot of money for my own poor ass starving college student budget, and I think that I'd rather get a track bike so I don't tear up my street bike. It'd be $700 either way. Maybe I can swing both if I get a decent job this summer.