I'll have to try the cuban 8 in the 767 next sim recurrent.
The 767 rolls beautifully as long as you're over 300 IAS...my party trick in the 767 sim is a aileron roll started at 50 RA and then a climbing steep turn, derry roll, flight idle then back around for a glide approach and landing.
Whether the real aeroplane could do as well is irrelevant...it's fun.
As far as upset recover is concerned the point is not necesarily about whether you can or can't simulate the G it's about recognising what is happening and using the controls as required to achieve brown side down without ripping the wings off or doing a supersonic lawn dart.
I personally think the 767, 737 are perfectly capable of being rolled...and I think the control responses when rolling the sim are reasonably realistic.
Chuck.