Model 7 was cataloged in 6.8 for a little while, but then they stopped.
700 SPS is currently made in 6.8
Strange really, since I might like a 7 in 6.8, but I can't see getting a full-size 24" deer rifle in the caliber.
That said, .260 or 7mm-08 give you more oomph in the same rifle.
Unless you get a compact semiuto like the Mini-14 or AR, both of which now are readily available in 6.8, or something like the CZ or Zastava Mini-Mausers, which aren't but should be, there's no real reason not to get a .308-family round.
Another cool package would be the Remington 7615 pump carbine in 6.8. Maybe they'll do that.