I did a similar thing, using heavy duty trailer jacks. See my post:
http://www.orangetractortalks.com/forums/showthread.php?t=38301
Now, to report on the good and "bad" about that design.
First of all, it generally works. I have not blown a shear pin from rocks so far this year. Started with the blower jacked up about 1.5 inches, while the base was packed down. Now, I'm down to about 3/4 inch and still working well.
I find one definite advantage. When turning with the blower in float (and on its wheels), the tractor is more likely to actually turn. With just skids, the blower would tend to keep going straight, and front wheels simply slipped. Only by slightly lifting the blower, could I turn with skids only. Wheels make a big difference in my case when turning in float mode.
Downside, on soft stone, the wheels still sink in just as much as the skids do. It all depends on how well packed the gravel is. I have areas that are hardly driven on, and the wheels will still sink in a bit. Have to watch it. Solution to this would be wider wheels I think. Mine are 2" wide. Something like 4" would likely make a difference. I have left the skids on the blower regardless, set to about 1/2" clearance, as a precaution.
I have had no issues with snow build up or jamming of the wheels, so far. Larger wheels may help also (mine are 8 inch diameter) I do have a set or 10 inch wheels, and a bit wider, so I may consider looking at those next summer.
All in all, I think adjustable wheels on snow blowers is a good idea, and should be standard equipment (or available option) for people with gravel driveways. I use a rear blade to scrape landing areas (concrete pads), and let the blower do the rest.
Good luck with your blower. I have to go out and blow tonight, just got 10 inches of the stuff today...