RE: Replacements Parts in general.
I look at it this way...
Given the price of the plane, more often than not I can either fabricate or fix most things myself and if not it's time for a new airframe.
Cowls, Canopies, Landing gear are all easy to repair or take care of once you learn how.
For most minor to medium frame repairs, I guage how much of my time it will take.... and use that to determine if it's worth the effort.
If it will take over six hours... it is time for a new airframe.
Some of the "big boys" sell a $140.00 airframe, then charge you $100.00 for a set of replacement wings.
Why bother? At that price I'll just buy a new plane and keep the old airframe for parts.
But to answer your question.
Most of the low cost ARF vendors are not supplied parts by the Asian factories, as this requires packaging and handling costs which those factories do not absorb.
Vendors such as Nitroplanes are forced to open a perfectly good plane, and take parts from it to fulfill requests for parts... ruining the previously sellable plane.
NP tends to do this for their customers... but the "fly in the ointment" is the availablity of plane shipments... which unfortunately are off due to the economy.
CMP for instance has reduced their shipping items only to a small handful of planes...
Tony / Andy have not been active on these forums for a while... you may want to try PM'ing them at RCDISCUSS.COM where they are more active.