Most of the DIY stuff is using off the shelf controller chips which are mostly self contained. That typically limits voltage and current rating. I have a couple of designs in work that use discrete components, and will come closer to the Gecko's, but it won't be as good as a Gecko. Personally I don't have the time and and equipment to verify a design. What I am shooting for is G201 like ratings, but, but will be limited to full/half/quarter and hopefully 1/8th step. No mid band compensation.
Unipolar 100+ volts similar amperage to above. Same step options.
Gecko's are awfully good drives for the price. They are proven designs, and have the support structure in place.
postscript: I'm still a couple of months away form having something, I just don't code software like I used to be able to :-(