re: ferry / train / bus model you can find them at a shop call 80M that has some branches across the city, and

CX office @ Harbour city for plane / cx stuff
KMB customer service center at star ferry

I like the idea for colonial flag item and may be current flag item as well

for old HK / classic HK feeling stuff, try browse at GOD, bit expensive but easier life http://www.god.com.hk/