craftgrrl | sewing puffed sleeves?

I've become completely enamoured with puffed sleeves, I think they are just so sweet!
I bought some amazing vintage fabric from the thrift store the other week, and I can just see it as a summer short sleeved blouse.

I've been looking at patterns, but I can't seem to find anything with puffed sleeves (and not like huge sleeves, something like this:

(built by wendy blouse!))

How would I modify a pattern to a lot more room in the top of the sleeve, to make it puffed, and how would i do the actually 'puffing' itself?
I've never actually sewn a blouse before, but I have used a pattern, and taken a sewing class, so I think I know a little about modifying patterns.

(cross posted to craftgrrl and sew hip..)