Join Date: Jan 2000
Location: Steelhead country|striper coast|bonefish belt
I'd say provided the rod flexes enough to let you employ the turbo-spey as Simon Gawesworth puts it, 50 feet should be achievable and with some practice more for a caster who can set a workable anchor and d-loop.
If it's a standard AFTMA 5wt line you're using, the shortness of the head portion may hamper the distance you can reach. Spey casts function better with a little more line involved in the d-loop, for instance the 5/6 windcutter.
Only one way to find out... try it!