A while ago i had a framebag made by Alpkit but since then i found myself in the position of being able to buy a bike i've wanted for some time, a Charge Cooker. The new frame is much bigger so rather than have a new frame bag made (and spending more money) I decided to utilise the extra space with a frame fit bladder holder. Bladder fitted in the picture is a 3 litre with the feed tube runninhg up the top tube to exit by the headset.
Before.

2005_0131bladder0002 by youngray50, on Flickr
After.

2005_0131bladder0001 by youngray50, on Flickr

Next project is.............seat cushions . A deal I agreed with the wife in order to buy the sewing machine in the first place .

That looks spot on! :)

a sensible solution to having too much space and not enough frame-bag - well done that man!

now get to those seat cushions...

That is excellent )

I like the idea of using a bladder in my frame bag, but creating space as I drink seems to be the issue - I like a tight-pack and rattles drive me nuts on the downhills, so seperating the two like that is a great idea. Stable in use?

Edit/ Reminds me, I have this from my alpine bumbling days, may work in a similar way.