A router style drill bit (like in the roto-tools) with a 1/8" shank will work in a Dremel style tool for the liteply.
You'll end up with fuzzy edges that a little bit of sandpaper will make short work.
For the triangle stock, you need to get the X-acto small aluminum mitre box and small zona saw.
A large pack of the X-acto #11 blades for the #1 knife handle will cut all the sheet balsa you need.

http://www.hobbypeople.net/inc/bigim...=94&height=150