Shouldn't be a problem, then. Of course, from having done this with a pre-load on my K2500 years ago (and only about a one minute load or so), you really have to trust that nothing EVER goes wrong with the load up, otherwise, you get to the end of setting your band up, only to discover that the load failed for some reason, and you still have the 40 minutes load time to do again.
The thing for me is, having found pretty much everything in a G70 to be adequate to do the gig (I've got a 64MB piano in ROM already!

), I don't find sample loading to be all that important. And, from listening to the Audya demos, you might find that, as far as the audience is concerned, neither do they. I thought the Audya piano pretty acceptable, myself. As are most of the other sounds. Me, I'd try gigging without any sampled instruments for a while before you hook yourself on what seem to be pretty RAM inefficient sounds that make a quick setup pretty tough to do.
Just curious, but does the Audya even allow you to specify a pre-load of multiple different sample sets, and make sure they always go to the same PC# addresses?
Having gone down this route before, albeit at a smaller level, I can tell you that, while in theory this is doable, there are often slip ups that make it a lot more touchy. Two minutes or so was not a big deal to do over. But 40 minutes? That's scary. I'd want to be absolutely SURE of the bombproof nature of the pre-load mechanism before I trusted that on a gig...