If you're talking about developing kind of prints... there is only 1 place in SG I know that provide this service. They're located opp Lau Pa Sak in Shenton Way. The name of the shop is Instant, a Kodak Pro Lab.
I used to go there and do my 20"x30", 60"x40" and the largest I ever did was 160"x120". But be warned, prices not cheap though. Remember ard $60 for 20"x30" and the 160"x120" cost me ard $500. However for me, I charged back to my client as these are commerical jobs.
If you're just thinking of printing for fun or hobby, cheaper option is to use inkjet prints... Sunshine plaza have a lot of shops that does this. Quality wise, slightly lose out to chemical develop prints. But it is acceptable. I used to pay ard $17 w/cold lamination for 20"x30". The largest size for inkjet prints there is A0 size which is ard 33"x47".
The above 2 places can request for cold lamination on the prints at a price.