I've seen a few but haven't really focussed on them as I prefer a smaller dog.
Bull/greys would have similar coat type, similar colour, assuming height and general proportions are additive, then yes I probably would expect them to breed fairly true to type. However as regards F1 versus F2 if there was a genetically deaf white bull parent then this might not be noticed as a problem in the offspring until breeding two lurchers with very slight hereditary deafness... and thus potentially getting a few pups with very poor hearing in the F2 (there are a few deaf lurchers around in rescues with a bull/grey look). Similarly F2 bedlington/whippets are very nice - nothing wrong with the shape/size/drive BUT you can't guarantee your pup won't die of copper toxicosis
so a F1 or a back cross to a whippet is much safer.
With labradoodles as I understand it the concerns are mainly about things that are (like the copper toxicosis) controlled by relatively simple dominant/recessive relationships. The labradoodle at the that start of this thread appears to be a take after a grandparent. Coat type is I think fairly simple (Sara maybe mentions it is a dom/rec somewhere in this thread
)
I wonder if you breed bull/greyhounds whether the litter number changes according to the generation? Just curious...