The simulation tool for Altera FPGA:s was pretty powerful when I used it a few years back. You'd basically drag and drop "packages" like the 74xx components, co

The simulation tool for Altera FPGA:s was pretty powerful when I used it a few years back. You'd basically drag and drop "packages" like the 74xx components, connect them and you could run the circuit with timing profiles and all. The purpose is of course not to actually then build it out of discrete logic but to synthesize it to a FPGA bit stream, but once you have the tool setup (it required something like 200 gigs if disc space and was extremely picky about drivers) I can see it being an option for this sort of thing.