We are a bit 'off track' here, but for Bruce - there is nothing to prevent a circuit at 200' AGL if ATC/airport regulations/obstacles and company limitations do not bar. I'm pretty sure that '1500' feet for jet has grown to become 'folk-lore' through the choice of it in standard circuit training in the sim and for real. 1000' is equally comfortable and safe for a big jet. As I said watching RAM many years ago scorching around CBA at 500' was enjoyable!
9.g - I have to disagree with you on the connection between an IAP and a visual approach. They are not bound together. The IAP can of course progress into a 'visual' but the visual does NOT depend on an IAP. I have many times arrived visually at varying parts of the visual circuit, anywhere between overhead and final, at different speeds and altitudes, at airfields all over the world - often without any form of IAP. All with the approval and knowledge of the relevant ATC unit. Without cancellation of IFR the responsibility for separation from traffic remains, of course, with ATC, but a simple check with them about your intentions - "xxx going around, request left-hand circuit" should cover that and you SHOULD yourself also be aware of the position of any possible conflicting traffic.