A busy few hours after my first attempt at a useful OpenSCAD design (http://www.thingiverse.com/thing:9446) and I've totally re-written and refactored the code into a parametric part library. It's still early days, but it already contains the basic building blocks and a bunch of basic parts (segments, nozzles, base plate).

There is also a demo section in the library that will generate a full set of example parts. Or you can un-comment the lines at the bottom to render individual parts and export the STL.

Module Structure
Basic building blocks are defined as chainable modules, taking at least one common parameter - the bore of the hose. Thus alternate hose sizes are trivial to generate (1/4 inch, 1/2 inch, etc).

Global Variables

• tolerance = controls the distance between the ball and socket surfaces
• definition = this defines the number of facets for curved surfaces (sets the $fn parameter)

Parts in the Library

• Hose segment
• Extended hose segment (user defined length of "waist" between ball and socket)
• Round Nozzle (user defined nozzle diameter)
• Base Plate (user defined screw dia, defaults to M3)

Feedback
Any and all comments welcome, it would be great if someone could print off a few segments and let me know if they work!

Updates
22 Jun 2011 - Uploaded v0.2 library, includes reduced wall thickness and increased distance between ball/socket surfaces (based on feedback from bohnded). Also added DoubleSocket module. For comparison, I've added a cross-sectional view of the latest hose segment alongside the loc-line part by charlespax - the ball/socket offset on my model is obviously still a bit tighter than charles', but not sure whether I should increase it further...?