I've done similar things, although in 4e rather than 3.5e. I think the technique is broadly applicable, but that 4e is a little more geared for the technique, as I will discuss below.
I generally took two approaches to things:
1) In cases where the PCs simply and completely outclassed the opposition, and I deemed there to be effectively no chance failure, I would tell the players, GM-to-players, "There is no chance of failure, here. We're not playing through this, we're skipping through to the end."
I would in these cases award no XP at all, because there was no risk nor any expenditure of resources. (By GM fiat.)
I never got any pushback or discontent from these decisions that I could perceive, because while some of my players liked combat, they generally did not like it so much that they wanted to spend precious screen time on challenge-free fights.
2) In slightly less lop-sided encounters, where there was no chance of loss but there was at least a chance they could get roughed up or have to spend some resources, I would offer (as opposed to the previous GM fiat) the opportunity of a streamlined encounter, such as: "Look, there's no chance that you'll lose, here, we all know it. But these guys could slow you down. I suggest we streamline this as follows...." with the proposal usually being something along the lines of everyone roll a check agaisnt some skill or stat, and if they fail they lose some replenishible resource.
In these cases, I would usually award some small amount of XP, but it was in general never enough to make a big deal about. I don't believe my players ever turned down that offer-- again, they liked combat, but they liked being challenged and they liked advancing the plot-- but I couldn't swear to it.
The first case, above, should be broadly applicable for 3.5e. What matters more than the rule set, per se, is what your players expect and desire from the game. If they really want combat, they might push back against this, unless you tell them you're just making more time for the more important combats later. If what they really like are effortless victories, well then you're depriving them of what they desire most in the game.
The second case is trickier and more rules dependent. 4e was geared toward the notion of skill challenges, which itself primed both players and GMs to think in terms of streamlining the boring stuff. Moreover, though, there were semi-standard, almost modular "resource chunks" to get rid of. You could say, and I often did, "...And if you fail the check, you still win, but your PC loses a healing surge." You could even follow it up with, "...and if you roll a 1, you lose the use of a daily power." (Assuming they had daily powers left; I'd also let them sacrifice 1/4 HP if they had no surges or didn't want to burn them for some reason.)
That would be the sticking point for the second approach in 3.5e: I can't figure out what you would offer in the bargain that would standardize across characters in 3.5e.