Unibus / Qbus bus drivers and receivers

I am just about to embark upon designing a small qbus interface card, and am trying to work out what to use for bus drivers and receivers. The 8641 quad bus transceiver is still available, but it appears that the 8640, 8881, 8131 and 8837 are all obsolete and out of production. I was tempted to use a pair of DS3862 octal bus transceivers since I want an internal tri-state bus on the card, but it looks as if the rise and fall times on the drivers are just a little fast (nominal 9ns compared to a minimum of 10ns according to the qbus spec). It would be really convenient to use these parts since it would help to keep the chip count down - any opinions on whether the faster rise/fall time would really be a problem in a small single backplane system? Also any suggestions for substitutes for bus drivers and receivers? I seem to remember the 7438 being capable of sinking enough current to drive a 120 ohm bus line effectively, but I'm not sure. (or, even better - anyone got a DCK11 chipset they would be willing to part with?)