I know sideless surcotes were more a 13th century thing, but how late did ladies still wear them? I am making one to wear to Faire on really warm days when something looser than a boned bodice might help me last the day without melting. I'm not obsessed with being H/A to the time period of the particular Faire I'm at, but just curious. Or, does anyone know of an alternative gown for the 1500's that might be a little looser/cooler to wear?
Looser, you could get away without a corset and do a Spanish Ropa.
You could do Margo Anderson's Elizabeth comfort pattern, which is a loose kirtle & overcoat. No lacing! http://www.sewingcentral.com/cgi-bin/Web_store/web_store.cgi?page=ma005.html&cart_id=502_4138
Also, Italian ren - think Ever After - is not so constructed & could be done in lightweight fabric to minimize weight/heat.
Most of the earlier Italian styles weren't corseted in the manner that we think of most Renaissance clothing.
http://homepages.wmich.edu/~rowen/renbk/rendressbook.html
This and the fewer numbers of layers make it more suitable for warmer climates.
http://www.costumes.org/HISTORY/100pages/italiRenlinks.htm
(http://alfalfapress.com/history/costume/images/1500_Boltraffio_lg.jpg)
Honestly, most sideless surcoats consist of a lot of fabric and are heavy to carry all day. I have one made with 14 yards of green linen. To get the full skirt effect below the hips takes a lot more fabric than most people realize.
My sideless surcoat garb is the warmest I have. That is partly due to the material I chose. But as DonaCatalina said, it is also a huge volume of material.
In addition, the very looseness that makes it appear cooler makes it appear ... sloppy for wont of a different word. It always feels like it's slipping from my shoulders or sliding around.
Oh, you're looking for an "Easy Dress!" A couple seasons ago, I decided I needed the same thing--something unboned, cool, easy to wear on the stupidly hot days.
I ended up going with a linen "gamurra-inspired" gown, which is sleeveless and open up the front (basically like an Irish dress). See it here (http://pic50.picturetrail.com/VOL417/1033223/17691164/275717823.jpg). (It's also the gown in my avatar.) It was inspired by this portrait by Botticelli (http://pic50.picturetrail.com/VOL417/1033223/17480040/321237253.jpg).
It's SO WONDERFUL to wear! The linen is incredibly comfortable, and when it's *really* hot I wear it over a lightweight cotton gauze chemise (because I don't yet have a linen one). What I like best about it, though, is that it closes with clasps instead of lacing, which is psychologically cooler. ;D I need to make more like it, because it really is the garb I grab most often because it's so easy and comfortable to wear.
Whatever you decide to make, definitely consider making the vast bulk from linen. It is THE BEST fabric to wear when it's really hot out, because it breathes and wicks moisture better than pretty much anything else. It's also soft, sturdy, and wonderful to wear. ;)
I found this lovely Venetian style sideless gown in the Tudor Shoppe web site. I thought it might help with your project.
http://tudorshoppe.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=LL-VND&Category_Code=WG