The others are right, DLGs (going with #1) may be a good way to get your feet wet. I've seen lots of composite-reinforced foamie DLGs at the field.
If you go the totally from scratch route, I'd hit the Modeling Science forum frequently. I found a ton of help there in coming up with a 'it might actually fly' design. You can check out my current endeavor along these lines: n00b Composite Scratchbuild 32" Slowflyer
. Adam's (wyowindworks) got a really cool inflation-bladder trick he uses. You can read about that and what's involved in mold-building on his (very frequently referenced) Making A Long Skinny Thingy.
Also Adam's right, you will probably want a vacuum pump. Plan on dropping $100 - $500+ (depending on the quality). I'd buy a higher quality mufti-stage rotary-vane model if you plan on sticking with composites for a good-long while. In that case, you'll probably also want a full vacuum rig with vacuum chamber and electronically-controlled wizardry