I doubt that. PCI-E standard will get faster before we start seeing 102 lane PCI-E northbridges.
Well, we're already getting close. Nvidia's SLI platform offers 40 lanes of PCI-E already, so we're almost halfway there. ATI's Radeon Xpress 3200 chipset offers at least 38 lanes off just the northbridge. As the technology advances, it'll become more and more possible; ATI's already preparing to launch a system with three PCI-E 16x slots. They'll be advertising two for video and one for physics, but really, you can populate those with whatever you wish.
I think it's more likely, though, that we'll see 2-3 16x slots and several PCI-E 4x slots, on future boards. There's no need for that many full 16x connections, and 4x PCI-E honestly offers enough bandwidth for most of today's or even tomorrow's secondary peripherals. (If Creative Labs' most powerful sound card today can run off a normal PCI slot, I'm sure they can live within the realm of PCI-E 4x speeds for the next several years.)
Besides, beyond that... it's more likely we'll see further integration and even less need for that many expansion slots at all. Basic audio is already integrated on practically all motherboards, and premium audio will likely become integrated into the video card, especially with things moving toward HDMI and its all-in-one audio and video connector. (ATI's already talked about how, beyond physics, spare cycles on a GPU would be suitable to use for audio processing.) With onboard GigE, onboard WiFi, and onboard RAID, most consumer-level things are becoming included already, making the upgrade card unnecessary for all but the most hardcore users.
That means that PCI-E cards themselves will ultimately be priced out of the mainstream market, something that's perhaps happening already. With so much of this stuff already integrated, what's the point in spending the money to design new hardware that natively uses the PCI-E 1x or 4x interface, unless it has a solid market willing to spend the money? Seriously, think about it. How many consumers need to buy a PCI-E GigE card? Those that truly could use that much speed are likely to have upgraded their computer recently anyway, and that means they've probably already got it on their motherboard.
That's why there isn't a plentiful supply of such things out there, nobody needs them. And nobody will, not in numbers like regular old PCI 10/100 cards were.
I'm sure RAID cards will continue popping up in PCI-E form, as will GigE cards. But they'll more and more be "premium" cards geared toward businesses willing to pay enough coin to make it worth the effort, as the mainstream gets left more and more with the full integration we're heading toward as our only option.
In fact, this AMD/ATI alliance makes it possible for PCI-E to be rendered obsolete entirely in the next few years; imagine a computer with only three chips, the CPU, the GPU, and the "northbridge" containing all the secondary peripherals you'll ever need, including GigE, "HD" audio, etc., all linked together with the HT bus. You could build a computer small and cheap that way--and it'd be smaller and cheaper if they left off all those expansion slots you're talking about. Most computers will be the size of small SFFs then because of the cost savings in materials, building, and shipping, and once the major PC retailers start seeing things that way, full-ATX-size computers with room for that much expansion will really drop off fast.
Yep, within 5 years, most computers won't even have PCI-E slots. There'll still be a market for full-size expandable PCs... but with the real volume of parts already being integrated into most machines, the market for expansion cards is already dwindling, and will continue to do so. I honestly believe the lack of PCI-E expansion cards on the market now is a reflection of that.