What do you mean about software emulation? This is hardware implemented inside an FPGA, not software and not emulation. I am confused now what you mean. Do you want to run a software on top of Mega65 core to emulate TED or VIC-I? It would be kinda slow still. And if someone really does a VIC-20 (or C16/Plus4) core, it probably would be a stand alone core so user can load M65 core or those, but how would you plan to "mix" them as you suggested? It wouldn't be so easy, and would result is a way complex hardware/VHDL design. And even that maybe the FPGA is not enough large anyway for a "super hardware clone" to capable of working as these quite large number of computers anyway. Other similar projects (FPGA arcade and such) also uses the theorem to have different cores, and not to "mix" those together, it's extremely hard, totally different timing, design etc etc.