Hope that the new push for FF will encourage Canon to come out with a few more designs quickly, but don't hold your breath.
I could definitely see Canon coming out with a 24-85mm f/3.5-4.5 IS USM in the near (within 12 months for announcement) future to match what Nikon is offering. Development of reasonable build quality, affordable FF zooms has completely died since 1998 (with the exception of 28-105mm II in 2000). Timeline of metal-mount non-L zooms:
Wide angle:
20-35mm f/3.5-4.5 USM (1993)
Normal:
28-70mm f/3.5-4.5 (1987)
35-70mm f/3.5-4.5 (1987)
35-105mm f/3.5-4.5 (1987)
28-70mm f/3.5-4.5 II (1988)
35-70mm f/3.5-4.5A (1988)
35-135mm f/3.5-4.5 (1988)
35-135mm f/4-5.6 USM (1990)
28-80mm f/3.5-5.6 I USM (1991)
28-105mm f/3.5-4.5 USM (1992)
24-85mm f/3.5-4.5 USM (1996)
28-135mm f/3.5-5.6 IS USM (1998)
28-105mm f/3.5-4.5 II USM (2000)
Tele:
50-200mm f/3.5-4.5 (1987)
70-210mm f/4 (1987)
100-300mm f/5.6 (1987)
100-200mm f/4.5A (1988)
70-210mm f/3.5-4.5 USM (1990)
100-300mm f/4.5-5.6 USM (1990)
75-300mm f/4-5.6 I/USM (1991), II/USM (1995), III/USM (1999) - non-Ring-type USM
75-300mm f/4-5.6 IS USM (1995) - non-Ring-type USM
70-300mm f/4-5.6 IS USM (2005)
All-In-One:
28-200mm f/3.5-5.6 I/USM (2000) - non-Ring-type USM
Not everyone interested in a 6D (when it finally comes out) will be interested in spending $450 for the OK-but-old 28-135mm or $800 for the 24-105mm ($950 un-kitted). There is definitely room in there for a $400-600 modern (latest IS version, ring-USM) normal zoom and a wide zoom cheaper than 17-40mm (maybe 18-35mm?)with at least ring USM (if not IS aswell).