I think I was the one with the thread dying before I got an answer from anyone. Anyway, the only singapore wholesaler that sells shock absorbing foam (use this instead of styrofoam) is AB Pac (
http://www.alibaba.com/member/abpac.html). Just drop them an email or call them, they will require dimensions and such before they will drop you an official quotation on the pricing.
Otherwise, if you are lazy to go and buy from them, you can walk in to Hobby Art Gallery at Sunshine Plaza (a shop that sells Gundam models, another hooby of mine ;) ) to buy shock absorbing foam from them. But they sell thinner sheets which you might need to stack and glue for a telescope. The biggest sheet they sell is S$16/sheet. The dimensions is around A2 size and is around 1-2cm thick (sorry, can't remember exactly how big and thick).
Personally, I dropped my DIY telescope case project. I decided to buy the Orion Observer's Backpack instead. I have an 8" SCT, so it fits into the bag along with other crap as well. At least lugging the OTA along with other accessories as well frees my arms to carry the mount and/or tripod, if they are too heavy for the bag.
You might want to consider that option.