Let me first say that I am an IBMer, and so I do have a certain bias here.
You may be able to find a printer which will print both PCL, PostScript and IPDS. Certainly in the cut sheet world, there are many printers that can. The Infoprint 2105 (http://www.printers.ibm.com/internet/wwsites.nsf/vwwebpublished/2090_2105home_ww) is an example of this, and your print volumes are well within its capacity.
BUT – you are a conforms shop. Maybe Oce has something, but you should consider this. Printing at rated speed in PCL above 150 pages a minute, you run into limitations inherant to the datastream. IPDS, the printer specific datastream for Advanced Function Presentation (AFP), is one of the most compact print streams in existance. On average, it is 1/3 the size of a PS or PCL datastream.
Another issue is that you are opening up your printer to any access. In my experience, in mainframe shops, centralized control of the resources remains important. I don’t know about you, but if someone from Finance decided to run a huge spreadsheet print job in the middle of my end of month reports, I would have his hide. As soon as the printer is “open” on the LAN, it is a target.
The nice thing about the Infoprint Server is that you retain complete control through the JES Queue over the sysyem. There is no cost for the xxx2AFP conversions, only to convert AFP to PCL/PS/PDF. The use of TrueType and OpenType fonts with Unicode encoding is something that we added into the 4000 and 4100 printers, and into PSF 3.4 (another free upgrade for your system). This allows you to print Unix, ASCII, and all native MS applications on your production printers, with no loss of control and minimal operator retraining.
So, bottomline, you will probably be happier with a cutsheet printer to print multiple datastreams natively. You will probably be happier with the IBM software solution with higher speed continuous forms.