I can't speak for others waiting on Klondike boards as I have a bunch ordered through Steamboat, but am tempted to wait for the rev2 boards that allow overclocking rather than accept a rev1 that doesn't.
I think you'd be better off getting them on v1 boards asap, to later decide to upgrade to v2 boards by either;
1) modifying some components and other firmware, another pcb might not be needed.
2) get v2 boards and transplant your avalon chips. Depending on the time between v1 and v2 this could still be beneficial (with difficulty rising sharply).
I think chances are that only minor adjustments enable substantial overclocking...not worth holding back your rig for...