IIRC the Naboo had screws that could, with a little elbow grease, be unscrewed. You could then scratch landing gear bays and glue them to the inside. Cutting the openings would be easier too. You might talk to the guys in the aircraft forum about gear struts. Cutting the openings you'll probably have to drill four small holes and use a small saw blade that is made for the X-Acto. The hull is rather thick on the bottom, but still lucky its styrene. Here's a few more pics of my conversion:
http://img.photobucket.com/albums/v72/ussarcadia/hullrear.jpg
http://img.photobucket.com/albums/v72/ussarcadia/carrierprogress.jpg
http://img.photobucket.com/albums/v72/ussarcadia/carrierprogress2.jpg
As far as help with dioramas, pick up a book or two on building them or visit that forum here. Lotta helpful people here as well as Starship Modeler:
http://www.starshipmodeler.net/cgi-bin/phpBB2/viewforum.php?f=7
http://www.starshipmodeler.com/gallery/gallery.cfm
First link is SW forum, second is the Reader Gallery which should have a few dioramas. The guys in the forum should be able to provide more links to dedicated SW sites.