Sounds like a good idea at first, but I'm not so sure if the collaboration of two artists who cover more or less the same field (although not always in exactly the same way) really makes the result "twice as good"...
From my taste and experience it's more rewarding when musicians collaborate who come from different directions, or at least play different instruments, so they can inspire, challenge and complement each other.
For example I think the duo Schulze - Tiepold was great, or Fripp and Eno, Mathias Grassow and John Haughm, Stephen Parsick an Markus Reuter or (a recent discovery for me) Steve Roach and Serena Gabriel.
On the other hand, on paper, Steve Roach and Robert Rich would seem like a dream team for me, however even though the albums they recorded together are, well, quite nice, but both of them made solo albums which are in fact better than their collabs...
Just my five cents.
.