We are a construction firm. We "lease" out our equipment to billable projects. Is there way to track the revenue through the FAM module or we will have to create a custom transaction record type?

FAM is for managing you fixed asset lifecycle i.e. for asset capitalization, amortization, lease accounting, some insuraence and maintenance cost etc . Nothing to do with revenue. Are you generation revenue using those FA ? if so then you have to use some other method outside of FAM. One idea tag your revenue transactions with the related FA then use analytics workbook or saved searches to do the reporting. There can be other way to do it too, its your choice

Yes, you can have revenue incurred and assigned to specific assets. There is a field for it on an SO form called "Related Asset" which is actually a dropped down field from FAM. The field is only good for reference though. There is also Income/Expense tab in FAM on an asset record. You would think they tie - but nuh. Yet, you can tie them with a script. You also can add all your maintenance costs on VBs in the same manner (Related Asset field and Income/Expense tab in FAM).