I can relate completely to your situation. I was at a point where I outgrew my position. Unfortunately for me, I was let go at the end of September. Even my boss admitted that I outgrew the position....
For my studio I took XEROX 7750 GX as a proof AND for banner printing because some jobs for clients are 3 or 4 A4 in row with 2 or 3 folds. On XEROX site for supported papers and size (http://office.support.xerox.com/srvs...on=r1010120977) you can see that printable area for banners is 302x1194 mm which is enough for 3 or 4 A4 with bleed for cutting. But max I get is 295 mm in height.
On the support site (LIVE expert) they always send me link for supported paers and size. No help or explanation how to solve my problem.
I would be very greatful if someone knows the REAL (in life) printable area for 7750 GX banner printing so I can use this machine for the reason I bought it for or to return it to XEROX.