I am not so sure that this is a good idea.
If one reads the comments about the various DDS units, a common problem area is controlling the noise.
Putting the DDS on the same board as the rest of the rig would produce an inflexible layout which may
or may not be problematic. The chances are very good that it would be...
In a way, it is the inverse of the problems associate with something like the AD8307. That device is so sensitive
to such a wide range of signals that it is mandatory to shield it away from the rest of the circuits.
With a wide-ranging DDS/PLL unit, one might produce things like birdies which are very hard to trace
and isolate. It's hard enough to think about designing a single (or dual) IF rig covering all of HF
with a wide-ranging VFO and getting it right. Even the best of the HF receivers (like the Sangean)
have birdies. One can hear them just by tuning through the whole range...
Why invite trouble?
john
AD5YE
