I've wanted a Tritium fob for years, but every one I find is way too expensive. So I purchased a green 3x22.5mm vial on eBay and modeled my own design. Before I print this on Shapeways (Stainless Steel) I am going to make a PLA version on my Makerbot Rep2 for final fitment and any tweaks to the model. I've already made adjustments to the design based on Shapeways analysis so I know I'm good so far.
I designed the bottom with a chamfered cavity to allow using J-B weld to hold the vial in place or possibly another kind of epoxy. I will do an update if needed after I perform a fit check in PLA.