One benifit of building engine for and racing Dirt Late Models all your life.... All the mail order oval track places have precisey what you want.
Bill Day has both the regular groover, the high dollar Van Alstine groover and all manner of blades to fit either.
http://www.daymotorsports.com/shop/Tires-&-Wheels/Tire-Accessories
Southwest Speed has the Van Alstine right on the front page and a couple of less expensive options further down in the catalog.
http://www.southwestspeed.com/
http://www.southwestspeed.com/?sec=...ries&ssub=Tire Groovers&sssub=Economy Groover
JR Motorsports - Note the site is kinda confusing to navigate....
http://www.jrmotorsports.com/subCategory.cfm?subCat2=764&subCat=695&cat=50
Prices are all within $10 or so - I'd look at the place closest to you to save on shipping.
I've used all of these groovers over the years and even cut some Boggers with them.... If your going to do a set for you only - The economy "Ideal" groover will work fine but take some time and effort on your part. If you even think you are going to do it for others buy the Van Alstine and charge for the work accordingly. For nice work on Boggers your going to need a good 4" angle grinder and those disk they sell for grinding rubber/tires.
Will