Most of them still exist and yes including in normal service.
So you could in fact almost completely recreate the protoype set and it would be realist to have a stabdard class 43 on one end with the surviving prototype power car on the other end if the electricals could be worked out because, obviously, the trailers have worked with both.
You could have the prototype livery on one side and use the other side and production power car, in turn, for the various in-service liveries. One caveat - as has been pointed out above, it would be a very long train to have to keep somewhere and would have high maintenance bills to match!
The only way this could possibly be viable is if it was kept in main line condition on a partnership basis and used on regular charter trains - not necessarily enthusiast bashes but all types of charter.
41170 is ex-41001 ( not the power car! ) with East Coast.
42353 is ex-42001 with Great Western.
42355 is ex-42000 with East Coast.
42356 is ex-42002 with Great Western.
42357 is ex-41002 with East Coast.
975814 is ex-41000 ( later 11000 ) in the NMT.
975984 is ex-40000 ( later 10000 ) in the NMT.
None in the Royal Train; that uses the former 11001 and 12001, three purpose built vehicles and four converted 405xx series TRUKs.