just say someone had some cough syrup containing pseudoephedrine, instead of goin through the normal route of diluting with Dh20 and cleaning and an A/B could one just say evap the whole syrup at the start and clean whats left?

Theoretically - Yes!
Realisticly - No  

For example - if you want 6gms of pseudo (5 x 200mL bottles @ 1.2gms/bottle), imagine how long it would take to evap 1 litre! Ages, I think.

Plus you would bee left with all sorts of sugar and other junk that my cause problems.

You COULD try just adding NaOH solution to the (alcohol free)syrup, and you should get FB crystals floating on top which must bee filtered out.