First, price a mainframe... not an exciting option (Score 1)

Before you get too excited about this, first price a mainframe. You first have to rewire your building for three-phase power, since they don't run on wall current. Then you've consolidated all your servers to one box, so you'd better have 24x7 uninterruptible power, and your current UPS generator likely doesn't supply 3-phase power. You also have to have adequate cooling, even with air-cooled z9 models. Then you have to buy a z9 (their entry level) and software, which is pretty expensive. Then you have to buy disk space. You will probably buy a x86 solution like the FlexES CUB, unless you can afford mainframe channel-attached DASD. Then you'll have to hire someone to care for this new beast, and good luck because no one learns about mainframes in college anymore. (Or, start on page 1 of the ABCs of Systems Programming five-volume set IBM publishes.... You won't be productive any time soon.) After that, you can start porting your programs to the zSeries instruction set, since you can't run x86 binaries. The only good news is you can run your Java programs as-is in the OMVS POSIX shell. Then you can start licensing the software every year.