Welcome to Librarium Online!
My best guess is that you could use 2 boxed kits and makea complete building, however instead of doing that you could always mess around with heavy cardboard to make you temple. Then stylize the sides with platicard for details and grabs some bitz and doodads from other building kits and there you have it; an awsome building for the price of less then one GW kit.
I don't know if you've seen this but it's an excellent site for scenery makers. Might help you with your temple thing.
No more NG spearmen, thanks! Now I need some pump-wagons!
or just buy intact sanctum imperialis bits at BWBITS.com.
That is not dead which may eternal lie,
for in strange aeons even death may die.