Scratch Build Controller. Again

This thread have been post in DYI-CNC. I am posting here in order to
validate the next high level design by electronics gurus



1) Driver would be able to microstepping. Looks like this guys are
selling boards for 10$ for PIC 16F84 with source code.
http://www.embeddedtronics.com/ < click over microstep >

2) Driver must manage current upper 7 AMP, well in the next link, you
get an schematic that permit manage 55V and 25A may be more. The power
circuit components cost about 43$ but there isn´t board or if it exist
you will need a skill soldering SMD components.
The schematic has an similar interfaz to LM18200, I think so.
Have a look at this link
http://groups.yahoo.com/group/osmc/
In the files section go the folder UMN OSCout

So the question is.
Do you think this design is realiable?
If answer is yes, it is worth the trouble waste a little bit time in
make a pcb board for point 2.

I would like your invaluable advice

Thanks in Advance