Very interesting topic... wanted to share my thoughts
I also have been wondering whether or not homemade ballistic protection is feasible. Initially I want to create a plate which can be used in
commercially available plate carrier vests, but ideally I would want a full body suit.
After all my research I basically came to two conclusions - the plate would have to be multi-layed with different materials, and should be configured
in a scale-armor design. I want to achieve Level III protection, which commercially means either 1/2" ceramic plate or 1/4" ballistic steel, or in
other words, high cost or weight. The other option (although only available to MIL,LE) is dragon skin, which has smaller round plates comprised of a
titanium plate and a ceramic disk, arranged in a scale design, wrapped in kevlar layers. The materials I figure would work the best together (and are
reasonably cheap and easily obtainable) are steel, polycarbonate, ceramic, ballistic gel, plastic, and titanium wire.
** NOTE ** I personally have not tested any of this ** NOTE **
Based on several conclusions I came to, in regard to how the materials reacted to gun shots, I came up with the following configuration
Outer Shell - Plastic shell that contains all the layers. Something I wanted to test was a titanium tri-weave incorporated into the plastic, or any
other type of fabric/wire weave.
Outer Layer - Polycarbonate, on top of a layer of ballistic gel, or any other type of gel that can create an 'air cushion' effect. I also wanted to
test the fabric/wire weave incorporated into the gel, rather then the outer shell
Mid Layer - Either ceramic (Mythbuster's experiment with bathroom ceramic tiles intrigued me) tiles or another polycarbote layer, sandwiched with
glass.
Inner Layer - Steel, thickness yet to be determined. This is the protective layer. Underneath the steel layer will be the padded layer (some sort of
high density foam), to reduce blunt trauma.
All the layers will be held together, and be made into 1" - 2" disks. Disks will then be layered into scale armor sections, one for each major
muscle group. All those different sections will be encased into a hard plastic shell for each body group.
The major technical problem is the overall thickness of a plate - I mean, it wouldn't surprise me if an armor like this would be 2" - 3" thick in
the end. I'd like it to be somewhere between 1" - 1 1/2" thick, that's a little more reasonable and should still allow for great mobility. Another
thing that would need to be balanced out is the weight, cost, and protection.
Weight - a vest, I'd want around 20 lbs, but thats asking for a lot lol. A full body suit, 40-60 lbs. Although, I had an idea for incorporating a
frame system, which technically, should take some load of the wearer - but that idea is a long way off.
Cost - Not really a main issue... i'd rather spend smaller amount of money for material over a long time period, then a huge amount of money in one
day.
Protection - I have no doubt that the various materials will stop bullets, it all comes down to how thick each layer needs to be. There are 6 rounds I
want to test - 9mm, .45 cal, 223, 7.62, 30-06, .50 cal (hang guns, rifles, snipers). Hand guns shouldn't be a problem, rifles I have my doubts,
sniper round, just wanna see what happens - who knows, may be pleasantly surprised
In the end, I'm looking to create something that is a cross between the batman begins and dark knight suit, with Level III protection. But first, I
wanna work on a simple alternative to armor plates for molle vests lol
- So there is a budget option I suppose, also a heavy wok
and a flat panel computer monitor were quite effective... 
