I have an Brand new, unused Drager electric O2 booster for sale. The details are found in the link below:

http://www.draeger.com/sites/en_aunz...er-DOB-MT.aspx

The booster lists for about $18,000, but is offered here for $12,000 OBO.
It is located near Detroit, MI for local pick up.
Drager describes this booster as a 'Mobile' booster, and I suppose it can be moved around, but it weighs a little over 200 lbs, so is really suited to use in one place. It can boost O2 up to 3500 psi into up to 4 lines/bottles at once from one or 2 supply bottles.
Drop me a line if you are interested in more info.