I can't suggest a solution in vhdl but I can suggest many other radio projects. **broken link removed**
AM receiver needs tuned filter and VCO to mix in IF filter best done in ceramic filters then AM demod, best done in analog.not vhdl.
Not necessarily. A software defined radio can esaily use direct conversion for the AM range. The analog front end would be comprised of a low/band pass filter, a pre amplifier and a moderate speed ADC. Refer to respective SDR projects.