DMC,
Right now I own three different arrangers (Yamaha 9000 pro, Ketron SD1 and Roland VA7); in the past I have also owned several synthesizers and workstations (Yamaha DX7 I and II, SY77 and SY99, Roland D50, D70 and JD880, Korg M1 and T3, Kurzweil K1200).
Among the arrangers I own presently one (the Yamaha 9000 pro) would no doubt fullfill all your requirements of reliability, resistance, etc. In my opinion it's the sturdiest keyboard I have ever owned and I am not talking just of the external appearance.
If you can find one to try out, maybe it will change your opinion about arranger keyboards being little flimsy toys, not reliable for a professional work, night after night.
Another good thing is that, even if you don't use the arranger section, it would still be a keyboard worth having in a studio, for its excellent sounds and DSP.

[This message has been edited by Dreamer (edited 04-25-2003).]