A light aircraft pilot reported an NMAC with another pilot at ORL.

Narrative

I contacted ORL Tower about 10 miles southwest with the ATIS information for landing. Radar contact was established and I was told to enter a 'right base' for Runway 7 by the Controller. I believe [the Controller] is a trainee. A right base for Runway 7 is unusual since that puts the aircraft south of the runway in or near Class B airspace restrictions for MCO. I continued inbound just south of the final approach course and was cleared for landing about four miles out. As I continued the approach straight in for Runway 7; I overheard Tower frequency radio traffic with an 'amphibian' that I later learned was a [small aircraft] on floats. This aircraft was cleared for takeoff on Runway 13. After he took off; I heard him request the Tower for permission to make a turn 'to the north' (which would put him across the final approach course for Runway 7). This request was denied by the Controller who said 'there is an [aircraft] on a two-mile final'. As I continued inbound established on the final approach at about 500 FT MSL; the [small aircraft] on floats suddenly appeared just below and in front of me in a right wing down attitude in what appeared to be a descent. I saw him for only perhaps one second. He immediately came on frequency and indignantly asked the Tower if they were talking to 'that [aircraft] that I almost collided with head-on'. The Tower confirmed that we were the traffic that he had been advised about. A [different] Controller came of the frequency and told the [small aircraft] that he had been denied a turn 'to the north'. I advised the Tower that the [small aircraft] had cut across the final approach course directly in front of me. I continued the approach and landed.