Sorry about nuking the post, we had a race condition :) I realized that all product names on that list [1] were clickable, and so I decided to first look at the products one by one and then come back with more specific questions.
Would Sketch Up work in your opinion? Also Mathematica is available under non-commercial license for $295, which is reasonable (and I always wanted a copy of it anyways).
[1] http://www.shapeways.com/tutorials/supported-applications
Ashlar has a lite version of Cobalt, called Argon - a commercial license costs $1200 or you can rent it [2]. There's also an educational license for $200 [3].
A less costly program that supports solids is TurboCAD, at $500 [4]. I've never used it, but like Ashlar Vellum, they've been around forever.
[1] http://en.wikipedia.org/wiki/Solid_modeling
[2] http://www.ashlar.com/3d-modeling/3d-modeling-argon.html
[3] http://www.ashlar.com/shop/3d-modeling-argon-stu.html
[4] http://www.turbocad.com/TurboCAD/TurboCADMac/TurboCADMACProv...
Edit: and if you want to make your cups parametric like the examples the grasshopper plugin for Rhino is the way to go http://www.grasshopper3d.com/