Has anyone created any custom approval routing workflow?

u mean on a custom record?

No on a standard record

yeah sure, what were u looking to do?

I want my workflow to do routing based on the limit. For eg:- if I assign a approver from a custom field for approval from a record. It should be assigned to selected approver only if he has limit for approving it or else it should be routed to next higher level.

what determines the limit? $ amount or how many approvals are pending in his current queue

Amount