Sorry this took me a while to get to ... Life happened.
(I made the links bigger to make them easier to spot.)
Here are the bits I used in my Gravity filter build:
Filter: Sawyer Squeeze
Adaptors: convert squeeze to hose barbs
.................The Sawyer Mini
has hose barbs integrated, so you can probably use it on it's own - A little lighter and a little smaller
Hose: Silicon Tubing
Various Hardware bits: Bulkhead connector - For going through the 'dirty' bag
Stem to attache tubing
Filter Adaptor for inside the 'dirty' bag
Pre-Filter inside 'dirty' bag
On/Off hose clamp
Series of Quick Connects used - you have a lot of options here
(You want the 1/4" In-Line Hose Barb styles)
Bag - From a 3-pack of dry-bags I got at wal-mart (they were pretty cheap)
I melted the hole using a socket of the proper diameter (can't remember what size, sorry) for the bulkhead connector.
Everything else pushes together.
Here is the link to the pics again: DIY Gravity Filter
I carry the whole thing within the other bags in the 3 pack - one for just the clean stuff, and the other for everything, including the clean bag. Nice and small!
Hope this helps.