Is there a small (6-pin) DIP I can use to generate multi-MHz squarewave clocks with an external crystal?
The LTC1799 can be programmed by a resistor and a link to produce a vast array of frequencies.


  Is there a small (6-pin) DIP I can use to generate multi-MHz
  squarewave clocks with an external crystal?



It's certainly small
It's 5 pins not 6
It's not DIP but you want "small" and DIPs are not small in comparison to SM devices.
It doesn't use a crystal