I'm not getting your point...
I think the point was that it's still possible to buy a new PC with "legacy" ports on it, IE, you don't need some hypothetical add-in computer-on-a-stick card to get them, nor do you necessarily have to dumpster-dive for an old PC.
I'm sort of confused what need a device like this is supposed to satisfy. If it's just about running the software modern CPUs are fully backwards compatible with 16 bit x86; most of the issues you'll have trying to run an ancient OS on a new PC relate to the less-than-perfect backwards compatibility of devices like VGA cards, disk controllers, etc. (many of which really only raise their ugly heads if you're trying to run something more elaborate than plain-vanilla DOS), BIOS incompatibilities like you may have seen on a real clone back in the day, or the old software simply being "broken" by exposure to a CPU much faster than it expects. (Plenty of us saw that back in the 386 days) You can resolve most of the hardware issues by using a hypervisor/virtualizer to set up a sandbox environment; VMware/VirtualBox/KVM/etc support "faking" a decently wide range of disk controller, video, and sound hardware and can run 16/32 bit guests on 64 bit hosts with a fairly insignificant performance hit. After all, hypervisors allow most CPU instructions to execute natively; on a CPU with VT-x support basically only hardware calls need to be intercepted and emulated. For software that *is* broken by massive speed increases game-targeted emulators like DosBox are an excellent fallback position. (For something like a DOS game it has to run "fast enough", why care if there's a lot of CPU overhead from the emulator if it achieves that?)
On the flip side, if this is about having access to genuine legacy hardware obviously a PC-on-a-PCIe card is going to have problems fulfilling that need. If you want it to have a full slate of legacy connectors it's going to be a beast of a thing and not cheap (look at units like the Sun PCi IIIpro, for instance; with a whole slate of dedicated I/O it takes up three slots), and if your needs involve ISA or something then you're looking at having an expansion chassis cabled to it as well. Going by what things like a Thunderbolt PCI chassis costs, and factoring the lower volume, I'm guessing a complete PCI-e PC+ISA box would cost somewhere well north of a grand to churn out. Not sure the market exists to bear that, but in theory I suppose such a thing might have industrial customers. But at that point the obvious question becomes: "why make it a PCIe card at all, why not just make a standalone PC motherboard with low end CPU, legacy ports, and an ISA slot or two tacked on?". It would undoubtedly be cheaper and more efficient.*
If you're really desperate to read floppies on a legacy-free PC a lot of them still have a parallel PCI slot. There may not be a good solution for getting a floppy controller into PCIe but there are several options for PCI. (Including Catweasels which are perfect for disk imaging, far better than a normal floppy controller.)
*EDIT:
Doh, of course you can get new motherboards with ISA slots. I should have known that. This is just one of many hits.
