How do you estimate market size for industrial machinery in emerging markets?

For Southeast Asia construction equipment, I'd start with ASEAN government trade statistics and combine them with WITS (World Integrated Trade Solution) import/export data — it's free and surprisingly reliable for machinery categories. Layer that with dealer interviews; local distributors usually have a gut feel for market volume that no database will give you. CECE and Off-Highway Research also publish regional reports if you can justify the spend.