Develop with FPGAs, but target discrete hardware?
There is something other than an FPGA which allows you to experiment with different circuits. It's the PSoC from Cypress. 



The chip contains dozens of digital and analogue building blocks. The digital blocks are a lot like those found in FPGAs, allowing you to create all kinds of digital functions: gtes, flip flops, adders, shifters, LUTs, etc. The analogue blocks allow you to create things like OpAmps, comparators, filters, a few values of resistor, ADC, DAC, etc.

The development environment allows you to literally wire up a schematic, and have it implemented inside the chip.



Having got your circuit working well, you might decide to re-implement it using discrete components. However, just as with the FPGA, the chip is capable of so much that discrete components could end up costing much more money and board space.