By having fibers in all directions(0/90,+/-45) you end up with a material that is comparable to an isotropicmaterial (metals ect) in that its properties are pretty uniform. Symmetry isrequired to reduce interlaminate shear stress as the upper face is deforming ata similar rate to the lower face. So for the lugs I would give (+/-45,0/90,+/-45) a go.

I personally would give the internalmetal lugs a miss, especially if you will be structurally testing the frame beforeyou park your rump on it, although you will need a jig to get the frame niceand straight. 1200g or lower is achievable for a 56cm frame.

Also there are other technical fibers(I think milled cotton is one) that can be used to drop the density of theepoxy making it ideal for making radii at the joints prior lamination.

Resin

I recommend epoxy over the cheaper vinylesterand polyester resins as it won't shrink during cure and it generally has bettermechanical properties all round. Considering that you probably won'tbe using an oven..... A slow room cure epoxy is recommended such as westsystems 105 with 206 hardener (decent marine grade epoxy.)

Formatof carbon and manufacturing process

Both tow and sheet are fine to use. Itis strongly recommend that you vacuum bag the lugs, it will make it a heck loadeasier to get the carbon to form the desired shape and it will make it significantlystronger as it will reduce the void and resin content if done properly. Alternativelythe cheaper and easier method is to use shrink tape but the end productprobably wont be as good.

Parlee use prepreg sheet (not really applicable due to absence of an oven) and usesilicone moulds to aid adhesion, although not completely necessary it is a nicemethod. 

http://www.youtube.com/watch?v=-Y0UK9W0Rl0

http://www.youtube.com/watch?v=22AnlUprKs0

Whereas from what I can tellcompanies like calfee just vac bag. In fact somewhere on the net Calfee has anice vid where you can see then using tow although given a quick search cannotfind it.....

Limitationsof bamboo

Woods would make a very competitiveframe to other materials if you could order the fiber orientation, but youcan't so I recommend the largest profiles possible for any element in torsion,i.e. the downtube and chainstays. This way you gain stiffness by the increasein its moment of inertia whilst not putting on too many grams thanks to the lowdensity of the material. This is exceptionally important if you are heavy (fora cyclist this is 80kg+,) like sprinting or just don't want a noodle of a bike.

To deal with the differentialexpansion I have been recommended to seal the bamboo with epoxy when it is atlow water content.

I hope my rant was of use and is the frame a conventional two triangle setup or something exotic?