QBUS/UNIBUS transceivers (again)

The driver is generally the easy part; there are quite a few FETs out there that ought to do the job acceptably. You need a total (driver + receiver) capacitance of 9.35 pf, which is generally the tallest order, but it's easy enough to limit the slew rate of the pulldown by putting a series resistor in line with the gate. I believe Peter Wallace recommended the FDV301N, which seems as good as any; put one for the driver and one at the source as a gate for a group of them, and you should have a pretty effective transceiver. It might take a bit of space, and you'll eat a lot in assembly if you're not doing it yourself, but as Dave McGuire pointed out, if your main logic is contained in a micro and/or CPLD/FPGA, you're going to have plenty of space. And for SOT-23 packages, you can probably get close enough to the density of the original (quad-gate) DIP devices. The FDV301N claims a Coss of 6 pf, though I haven't done my homework to think about how the other parasitics affect the input capacitance.