I haven't looked at Bob Blick's schematic yet but what is wrong with the 
'classic' H bridge using 4xNPN 2xPNP and 4 resistors ? It sounds like 
you want low cost before anything else. This circuit will not regulate 
motor speed but if you could output slow PWM (say 100Hz) from your 
control and relate it to voltage then it would do that too. At that slow 
rate the energy pumped by the L kickback is low enough that you can 
ignore it for heating purposes (even more so if you slow down the switch 
with two small caps). When you said cheap, did you mean parts count ? 
This solution uses 10 or 12 parts (with the caps) but they are very 
inexpensive. BC547/557 covers your current range.

Motorola make some nice motor driver chips some of which work down to 
2V, using mosfet switches and a built in charge pump for gate power. I 
don't think that the price can compete.

Peter
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