have a look at an 1800 cvh from a sierra to see if the pick up is on the crank pulley . if it is that should be quite straight forward to convert .
a pinto/cossie pulley has notches sticking out of it so isn't seperate . the pulley wouldn't fit on the crank.it would be also quite difficult to set the right air gap on the sensor to the pulley , and getting it in the right place could be tricky .you dont want reliabilitie to be an issue . the spark has to be spot on . one degree the wrong side and running problems may occur .

WEBCON . make management bits and pieces . mainly for zetec converted caterhams . Last time i spoke to them they did make aftermarket crank pick ups for crank pulleys . if you like i can see if i still have thir number when i get to work tomorrow.
i think an aftermarket kit may be the way to go if you dont fancy dropping the engine down again