Substitute for 455 kHz Ceramic filters in new designs
Looks like you have two alternatives:

1) Go forwards : as Marcus says, use a decent low pass filter (or analog bandpass filter if undersampling), sample in a fast ADC, and implement the required bandpass in DSP or FPGA.

2) Go backwards : study IF circuits that pre-date ceramic filters. These were generally multi-stage LC filters, based around IFTs where the secondary winding controlled the coupling between tuned circuits. Nobody can stop you winding your own inductors...