From what I've read so far, there isn't any difference from the 2006 to 2007 2500HD Classic. The truck for 2007 is the same as 2006. The change will come in approximately September or October with the new emission standards. So it will be safe to buy a new 2007 2500HD Duramax with the price only being about $300 more and have the same truck as a 2006. So if you can't find what you want in a '06 get an "early" '07 and get the same engine, as in Duramax. Right? Will the colors be different?

Except for a few very minor changes to some equipment options, the 2006s & 2007 Classics are identical, but the 2006s are thousands of dollars less expensive because of the factory incentives.

For instance, on a 2500HD, here are the changes from 2006:

2007 Chevrolet Silverado 2500HD Classic
Deletions:
(LLY) Duramax 6600 Turbo Diesel V8 engine
(ML6) 6-speed manual transmission
(VCL) Emissions, CFV (Clean Fuel Vehicle) LEV (Low Emission Vehicle)
Changes:
(UC6) AM/FM stereo with 6-disc CD changer audio system now available on 1LT
(UK3) Steering wheel controls now included on 2LT
(V76) Recovery Hooks now standard on all models

2007 GMC Sierra 2500HD Classic
Deletions:
(LLY) Duramax 6600 Turbo Diesel V8 engine
(ML6) 6-speed manual transmission
(VCL) Emissions, CFV (Clean Fuel Vehicle) LEV (Low Emission Vehicle)
Changes:
(UC6) AM/FM stereo with 6-disc CD changer audio system now available on 3SA
(UK3) Steering wheel controls now included on 3SB
(AU3) Power door locks now available on 1SA without Fleet or Government order types
(V76) Recovery Hooks now standard on all models

Just for fun I built up a 2007 with everything I wanted and as you said the cash rebates were only $1500 on the LBZ compared to the $3000 on the '06 models. Thats a real incentive to buy this weekend to get the larger rebate. Hope they change to larger rebate real soon.

The loaded models seem identical.