I've create a box based on Ubuntu 10 and fluxbox as a 5250 terminal for our plant terminals.
I still have problems with xt5250 keyboard assign, but one feature I tried to emulate from the IBM iSeries is a front-end to the session printer. AFAIK there is no such application.
So, I've write a small ruby application that shows the status of the printer. It uses tk/tcl and wraps around lp5250d.
Instead of run lp5250 session_profile (from .tn5250rc), you replace it with lp5250_gui.rb session_profile.
If there's anyone interested in testing this, please drop me an email (vjsmoreira at gmail dot com), or access my profile in linkedin (http://pt.linkedin.com/in/vjsmoreira
"The best is (always) yet to come"