Well for the Slave one ! I have no idea ! if there are Aftermarket parts for it... I doubt it !
but there are parts for the Star Destroyer ! and Millenium Falcon ! and X-wing, Darth vader Tie and the Arc-170
http://www.starshipmodeler.biz/index.cfm?fuseaction=category.display&category_id=42
at Starship modelers they have a few !!! not always in stock but you can keep an eye open for them...
Also Arvey models products have a Brim trenches and Spin and other accessories for the AMT star destroyer.... to make it either ANH or ESB style....
http://www.freewebs.com/arveymodelproducts/
I got some a while back and they made the AMT kit shine !!!
Odyssey Slipways also carries items for the AMT Star Destroyer ! available thru the SSM store.
as for the Speeder bike the only part I would recommand is the 4mm soft steel spring offered by Mechaskunk.com you need one of the 12" one to complete the Bike Power conduits.
http://www.mechaskunk.com/store-mms.htm
I used them on all my bikes and I will never go back !!!! enough said !
For the AMT B-wing I don't know !
A-wing... don't know
AMT AT-AT ..same story...
and thank you for the great comment in reguard my Scouts !
Since there were None on the market.. I ended up making my Own ! Now working on No 9
Hope this can Help ?
take care and Don't forget the pictures...
See ya !